Tell MAMA is the only pressure group that undertakes the hard but necessary work of encouraging Muslims to report religious assaults. MAMA stands for Measuring Anti-Muslim Attacks and its workers use the information it collects to persuade the police to take sectarian violence seriously.

I admire Tell MAMA because it follows the cases that rarely get national attention: reports that Ulster loyalists are behind threats to Muslims in Northern Ireland or news of yobs insulting worshippers when they leave a mosque. It ensures that abuse of Muslims does not become an accepted fact of British life and offers a way into a criminal justice system, which is meant to protect their rights.

Naturally, Tell MAMA and its founder, Fiyaz Mughal, have enemies. They receive, as one might expect, racist abuse from supporters of the English Defence League. The rightwing press isn’t much better. Mughal despairs of the “there’s no such thing as Islamophobia” pieces that do the rounds. But it is not the “Tory press” that is stopping Tell MAMA from holding meetings in mosques. Nor is the EDL threatening to destroy its efforts to contain anti-Muslim violence.

Those squalid victories belong to the Islamist right. “We are being targeted by charlatans who are leading Muslim communities off a cliff,” Mughal told me. “I think we have 18 months before we lose a generation of young Muslims.”

If you are astonished that a charity fighting Islamophobia is being targeted by Islamists then you have no right to be surprised by the manner of the attack. Across our hysterical country, the supporters of the “new politics” seek to turn their opponents from reasonable people with ideas worth debating into the enemy, the alien, the “other”.

For Corbyn and his comrades, doubters are automatically “Tories”. They may have been Labour supporters or, indeed, Labour MPs all their adult life. They may have intelligent leftwing objections to Corbyn’s willingness to indulge every form of anti-western violence on the planet. They may even oppose Corbyn on the unimpeachably anti-Tory grounds that he is guaranteeing a decade of Tory rule.

Their motives do them no good. They dissent, therefore they are “Tories” or, more often, “Tory scum”. Scottish nationalists, meanwhile, exploit their version of the “no true Scotsman” fallacy. In the SNP’s mind no true Scotsman (or woman) can harbour doubts about independence. Those who do are English stooges, agents of a foreign power, who are guilty of “talking Scotland down”. Just as the only way to prove that you are not a Tory is to support the Labour leadership, so the only way to be a patriotic Scot is to support the SNP. These are the paranoid tactics of a religious cult that holds that everyone outside the circle of true believers is tainted by the sins of the devil and all his works.

The enemies of Tell MAMA, an organisation that fights Islamophobia, you will recall, hold that “no true Muslim” can support it. Renegades who do are Islamophobes. Muslim Engagement and Development (MEND), an outfit that previously operated under the banner of iEngage until controversy forced a rebrand, has decided that the worst it can say about Tell MAMA, the best means it can find of turning it into a satanic organisation, is to say that it associates with gays and Jews.

I am not exaggerating. In November, MEND’s chief executive, Sufyan Gulam Ismail, announced to a Manchester mosque: “We don’t want the government to fob us off with some phony thing called Tell MAMA, which has got a pro-Zionist pretty much heading it, or in a very senior capacity, and is making all sorts of comments we might not agree with when it comes to homosexuality, to be recording Islamophobia.”

Tell MAMA’s offence is to try to be consistently anti-racist. When it decided to monitor anti-Muslim hatred, it turned to the Jewish Community Security Trust for help. The trust gave it willingly. “We believe our shared experiences can help to bring communities together,” it said, and the trust’s former chief executive Richard Benson became co-chair of Tell MAMA.

Peter Tatchell, who has endured anti-gay hatred throughout his life, also wanted to do what he could to fight anti-Muslim hatred and joined the board.

The real reason for the insults Tell MAMA receives, for the accusations that it is friends with “paedophiles”, “Zionists” and what modern anti-semites coyly call the “Israeli lobby”, is more profound, however. Mughal believes that, if it is wrong to attack a Muslim for being a Muslim, then it is equally wrong to attack a gay man or a Jew for being a gay man or a Jew.

Put in these terms, the Islamist campaign against an anti-Islamophobia monitoring service is less astonishing. Tell MAMA’s enemies can never accept that Muslims should find common ground. Islamist prejudice must never be questioned. If British Muslims turn into Islamic State murderers, it must be the British government’s fault and anyone who says otherwise must be an Islamophobe.

Nor is the hounding of liberal Muslims as astonishing as it should be. I have enjoyed the Guardian for decades. But too many of its contributors have lost their wits and abandoned their principles over radical Islam. They show no signs of finding either soon. As a matter of course, they publish a defence of the silencing of Maryam Namazie, an ex-Muslim feminist, or a piece denouncing Maajid Nawaz, the Muslim leader of the anti-extremist Quilliam Foundation.

In academia, speakers at Bath University, surely the most malign higher education institution in Britain, call ex-Muslims “native informants”, as if the decision of free men and women to decide for themselves what they should believe is the equivalent of collaborating with a colonial oppressor. For the religious right and the political and academic left, a liberal Muslim is their trussed-up version of the enemy, the alien, the “other”.

None of the above is astonishing. It’s been going on so long that we accept it as the “new normal”. What is astonishing and frightening was the look on Mughal’s face when I finished talking to him. He looked defeated. He thinks the extremists are winning and that Britain does not begin to understand the trouble that is coming.