What do Colin Ward, the late education officer for the Town and Country Planning Association, and a squatter in London have in common? The answer: they're both anarchists. Or rather, the squatters have been dubbed anarchists by the media; Ward was an anarchist of his own volition.

It's strange to think that a well-respected public figure such as Ward could be openly allied to anarchism, a tradition currently associated with ruining the royal wedding or vandalising shops on Oxford Street. But the truth is, anarchism isn't simply a byword for criminal damage. It's a broad-based political philosophy – one which accommodates people of significantly contrasting viewpoints. Thus, Ward could call himself an anarchist, yet spend most of his life championing tenant co-operatives and died never having smashed a single window.

The problem with the contemporary media narrative on protest is that, in its refusal to understand the nuances of anarchism, it is using the term as a euphemism for "dangerous", "violent" or "bad". So when the Telegraph reports that 100 masked anarchists were "thwarted" by pre-emptive arrests before the royal wedding, it encourages us to make a judgement on those arrested. They were anarchists, we think; ipso facto, they must have deserved it.

The dangers of this way of thinking hardly need explaining. There are flickers of McCarthyism in the way the state is currently dealing with those it perceives as threatening. Potential anarchists are intimidated and smeared, and denied liberty on the grounds of nebulous and almost Orwellian charges. Protester Charlie Veitch, for example, was arrested "on suspicion of conspiracy to cause a public nuisance", which is something we should apparently be relieved about – because, according to the Telegraph, he's a "known anarchist". Although we should be careful not to exaggerate the issue, I must admit I notice parallels between the police's recent actions and senator Margaret Chase Smith's condemnation of McCarthyism. She argued that the practice fundamentally inhibited "the right to criticise; the right to hold unpopular beliefs; the right to protest; the right of independent thought".

There are other recent examples of suspected anarchists being the victims of McCarthyist policing, ostensibly in the name of national security. In 2009, French police raided the small village of Tarnac, including a farm consisting of goats, chickens and vegetables, believing it to be an "anarchist terrorist cell". The alleged ringleader, Julien Coupat, was jailed for six months despite a judge's ruling that he be released. This decision led other residents of Tarnac to accuse the French authorities of fabricating "an enemy within", and in doing so, labelling all forms of leftwing demonstrations and activism as anarchist terrorism. Coupat and his friends, like the alleged anarchists that were arrested in squats last week, had attended several demonstrations opposing French and American government policy.

The raid of Tarnac is unsettlingly reminiscent of the recent police raid on Transition Heathrow; a grassroots community that describes its aim as the promotion of "green, living, working fellowships". As with Tarnac, the 40 riot police that descended on to the site found nothing but vegetables, chickens and bees. Spokespeople at Transition Heathrow commented: "If all [the police] wanted was a tour round, they could have just taken off their uniforms and we would have given them a full tour. They might have even got a cup of tea."

There are very few people in this country who have an issue with the police responding to crime. But the decision to criminalise a political philosophy veers dangerously close to the criminalisation of thought; and a society that uses those tactics can no longer be called civilised. If we truly value civil liberties, we should interrogate the pejorative use of the word "anarchist" because the alternative, it seems from recent events, is for the police to use it as a baton with which to beat us.