On Thursday afternoon in Birstall, Yorkshire, Jo Cox – a Labour MP, a tireless campaigner for social justice, for refugees, for women, for her constituents, and a mother of two young children – was shot, stabbed and killed.

The suspect in her attack has links to far-right groups. He was heard to shout “Britain First”, the name of a far-right, anti-migrant, anti-Europe thug club masquerading as a political party, by three witnesses.

Today, commentators and apologists are scrambling to make this tragedy anything other than political. That is an insult to the memory of an activist who dedicated her life to the politics of hope and inclusion. It is also a monumental cop-out.

When a tragedy like this happens, as it does with frightening frequency in these sour times, we ask ourselves, inevitably, ‘how and why?’ We take sides, we point fingers, we seek answers, and when those answers come up short and hurtful, we throw up our hands and declare it all senseless, without possible affect, and in this manner we are able to look at our collective faces in the mirror without retching.

Michael Adebowale, one of the killers of soldier Lee Rigby in 2013, also had a history of mental illness – but the press did not focus on that history. They focused instead on his religion, on the mangled political manifesto he mumbled at passersby, his hands still covered in another young man’s blood.

Tommy Mair, the suspect in the death of Jo Cox, is white and British, and as such is already being described as a “lone wolf”, as “timid”, a disturbed individual. He likes gardening. He volunteered in his Yorkshire community, the Daily Mail reminds us, and his membership of far-right, anti-EU groups can have had little to do with his decision to gun down a left-wing, pro-EU politician who led campaigns to bring Syrian child refugees to Britain – a campaign that was rejected by a Parliament in thrall to the naked racism of the tabloids.

We have seen all of this before. Disturbed man commit acts of unspeakable violence, and that violence is dissected and dismissed on the basis of their skintone, faith and nationality. Attackers are divided into binary camps of “terrorist” and “lunatic”, as if hateful ideologies and individual derangement can never be related.

So, one man who killed 49 people in a gay bar gets to be a terrorist; another man who shot and stabbed a left-wing politician gets to be a mentally disturbed loner.

Ask yourselves what these explanations have in common. They are excuses that allow us to place the blame for violence outside ourselves, outside society. They allow us to look at patterns of brutality and see nothing that implicates our leaders, our communities, our consciences. The meme of performative attack is spreading and replicating like a virus in the Global North, and we try to explain it away, because it’s easier that way, because that way our hearts might not break.

Do not ask whether these killers are crazy. Ask instead how people are going crazy right now, and why, and where that sickness begins. What makes a man kill a stranger? If we ignore his manifesto, the slogans he shouts as he is tackled and taken down, what else could it be? Is it our broken, underfunded mental health services? Is it toxic masculinity? Social isolation? A culture that strips ordinary, vulnerable people of hope and dignity, offers them no justice, no jobs, no sense of agency? Can we think of any more questions to which the answer is yes?

It is all of these things and more, and none of them work as excuses. Sometimes, people break. And sometimes there is a pattern to the cracks.

It bears repeating that people with mental health problems are not, in general, dangerous. The mentally ill are, statistically speaking, far more likely to be the victims of violence than they are to perpetrate it.

In fact, the epidemic of anxiety and depression is almost certainly one of the reasons we don’t have more riots than we do. Most people who lose their grip on normality do so in far gentler and more self-destructive ways. They break down; they collapse in on themselves. They turn their rage and bewilderment inwards. Unless they have a particular disposition and a good reason not to. Such as hate-preachers peddling a refrain of vicious victimhood that tells the vulnerable that violence is a way to save your soul.

Right now our society is full of lost, angry people looking for someone to blame. Right now, our culture is captured by swivel-eyed demagogues only too happy to take that blame and direct it for their own political ends. Racists, xenophobes, homophobes, misogynists, religious extremists and right-wing fanatics, all offering their own lyrics to the same chorus of fear, the same promise to restore your lost pride if you only march along.

This is not simply a question of terrorism, or of mental illness, easy as either of those answers would be. It’s both, and more. It’s hate-groups preying on the broken and hopeless and fearful, and we are letting it happen.

Sometimes people break down. And sometimes societies break down, and if we are using the language of sickness, the sickness is inside us.

Something has gone badly wrong in this country. Something has gone badly wrong in America, and in the rest of Europe. The centre cannot hold; deep cracks of violence and suspicion crawl in from the fringes of public opinion to rend the heart of the political consensus. Ruthless shysters exploit the rage of the most vulnerable, of those cheated and tossed aside by austerity and inequality, and redirect it towards the marginalised, towards outsiders.

Opinions about migrants, Muslims, women and poor people that would, scant years ago, have been unspeakable if not unthinkable are now part of public discourse. It doesn’t matter that half of us think these opinions are bigoted garbage: they are being discussed at the highest levels of public debate.

On the morning of Jo Cox’s death, Nigel Farage, the two-faced pettifogger leading the toe-curling Brexit campaign, unveiled a poster showing a horde of brown-skinned refugees advancing on rural Britain. The slogan was: “Breaking Point”. That is not “dogwhistle” racism, because everyone can hear it, and now we all have to swallow our bile and respond to it.

The career politicians, internet extremists and tabloid writers peddling hate in Europe and America today did not hold the guns that killed 49 people in Orlando. Omar Mateen did that. They did not buy the weapons or hold the knife that killed Jo Cox. Tommy Mair was arrested for that. But they offered the logic that moved the hands that pulled the triggers. And nobody else is offering any answer to millions of other frightened, angry people failed and humiliated by the system and their own self-hatred.

The sickness is already inside us. The craziness is chewing away at the heart of our society, of our politics. It cannot be explained away, and we owe it to ourselves and to the victims not to write it off as affectless terrorism or meaningless madness. It is hate. There is a logic to it. That logic is being exploited by unscrupulous scumbags, to everyone’s shame.

Jo Cox’s husband Brendan, a campaigner who today will have had to explain to his young children why their mother won’t be coming home, was quite clear in his statement to the press:

“Jo believed in a better world and she fought for it every day of her life with an energy, and a zest for life that would exhaust most people.

“She would have wanted two things above all else to happen now, one that our precious children are bathed in love and two, that we all unite to fight against the hatred that killed her. Hate doesn’t have a creed, race or religion, it is poisonous.”

It’s not too late to pump this poison out of the system. One brave woman is dead. Others must work now to emulate her example: to place compassion above fear, hope above hatred, to fight against the intolerance tearing apart our communities. To work and speak and vote against bigotry and blame.

This is a dark, ugly day for democracy. There may well be more to come. But if more of us can muster the courage of Jo Cox, it won’t be dark forever.