Warwick University Student Union’s reversal of its initial decision to bar me from speaking about Islam and Islamism on campus, at the invitation of Warwick Atheists, Secularists and Humanists Society, has been widely celebrated as a small win for free speech. But it has also ruffled the feathers of Islamists and their apologists.

Historically, criticism of religion has been a crucial aspect of free expression and intrinsically linked with anti-clericalism and the dismantling of that which is deemed taboo and sacred by the gatekeepers of power. Such criticism has been key for social progress. It is also a matter of life and death for many living under Islamist rule, such as in those areas where Isis has seized power, Saudi Arabia, or in Iran where criticism of religion and the state are analogous. There, anything from demanding women’s equality or trade union rights to condemning sexual jihad and the “Islamic cultural revolution” (which banned books and “purified” higher education) can be met with arrest, imprisonment and even the death penalty.

Where Islamists are not in power but have influence – I include Britain here – critics face accusations of racism and Islamophobia to deflect legitimate outrage against Islamism, which I regard as a killing machine and a network with global reach. Atheist bloggers have been hacked to death by Islamists in Bangladesh while UK-based Bangladeshi bloggers have been placed on death lists.

The labelling of much-needed criticism of Islamism as antisocial, even dangerous by left apologists sees dissent through the eyes of Islamists and not the many who refuse and resist. How else are we to show real solidarity with those who struggle against the theocracies we have fled from – if not through criticism? The fight against Islamism and the need for international solidarity apparently does not enter into their calculation.

Even their paternalistic “concern” for British Muslims is incoherent. After all, aren’t many critics of Islamism Muslims too? In fact, Muslims or those labelled as such are often the first victims of Islamism and are at the forefront of resistance. Also, not everyone in what’s referred to as the Muslim “community” is a Muslim, and even if they are, religion is not the only characteristic that defines them. Moreover, the rise of Islamism has brought with it a corresponding rise in the demand for atheism, secularism and women’s liberation.

At its core, this is a global fight between theocrats and the religious right on the one hand, and secularists and those fighting for social justice on the other. It’s a fight taking place within and across communities and borders. Notwithstanding, the “concern” of this “left” only encompasses the “authentic Muslim”, which to them is the Islamist. It has become their go-to catchphrase to deflect all criticism by dishonestly conflating condemnation of Islamists with the demonisation of ordinary Muslims, so as to justify siding with the religious right at the expense of dissenters. In fact, conflating ordinary Muslims with Islamists does nothing to challenge anti-Muslim bigotry but in fact reinforces it.

In their “anti-colonialist” worldview, which unsurprisingly coincides with that of the ruling classes in the “Islamic world” or “Muslim community”, dissenters are either “native informants” or contributing to the “demonisation of Muslims”.

For those who have bought into the Islamist narrative, there are no social and political movements, class politics, dissenters, women’s rights campaigners, socialists – just homogenised “Muslims” (read Islamists) who face “intimidation” and “discrimination” if an ex-Muslim woman speaks on a university campus.

This politics of betrayal ends up denying universalism, seeing rights, equality and secularism as “western”, justifying the suppression of women, apostates and blasphemers under the guise of respect for other “cultures” – imputing on innumerable people the most reactionary elements of culture and religion, which is that of the religious right. According to this view, the oppressor is victim, the oppressed “incite hatred”, and any criticism is bigotry.

Ironically, these postmodernist “leftists” have one set of progressive politics for themselves (they rightly want gay marriage, women’s equality and the right to criticise the pope and Christian right) and another for us. We are merely allowed to make demands within the confines of Islam and identity politics and only after taking note of the “power imbalance”. (By the way, an ex-Muslim migrant woman like me is a minority within a minority but that “power imbalance” does not concern them.)

Islamism must be challenged by an enlightenment, not a reformation. (Some would argue that Isis is Islam’s reformation.) For this, the right to criticise religions and the religious right (including the Christian right, Buddhist right, Hindu right and Jewish right) is crucial, as is international solidarity and an unequivocal defence of migrant rights, secularism, equality and citizenship.

Those in the business of defending Islamism make a mockery of traditional left values and are incapable of fighting for social justice on multiple fronts – these include fighting against the religious right, racism and xenophobia, fascism of all stripes, the UK government’s restrictions on civil liberties, as well as for free expression.

Now is the time to reclaim the left and the values it represents for us all – irrespective of “community”, beliefs and borders. In the age of Isis, this is an historical task and necessity.