This week, along with other students, we started a petition to stop Professor John Finnis teaching at Oxford University. As anticipated, the petition has been criticised on the grounds that its proposals would undermine academic and – though Finnis himself says his views are “strictly philosophical” – religious freedom. We were called “snowflake” students who were simply incapable of arguing against opposing views. We believe these criticisms miss the point.

Here are some of the reasons for the petition: in a 1995 paper Finnis sets out that the judgment that homosexual conduct is “evil” can be defended. He draws an analogy between the “copulation of humans with animals” and homosexuality. In a 2011 article, he laments restrictions on the discussion of “the reversibility of sexual orientation or the relation if any between sexual orientation and child-abuse”.

We’re not incapable of arguing against these views; they are poorly reasoned and incoherent. Instead, our argument is that students should not encounter them from their teachers. Our petition argues that we should draw a line when professors dehumanise disadvantaged groups. Apparently, some critics think that this is too radical.

The desire that discrimination be understood more accurately is what drives our call for policy change

Some accept that Finnis’s views are discriminatory. However, they argue that they are nevertheless protected by “academic freedom”. This response is simplistic. Rather than reciting cliches these critics would do better to explain what academic freedom is and what its limits should be.

We think the petition sets a reasonable limit. Academic freedom is not best judged in the abstract. It is about students and staff. It is about power dynamics and systems of disadvantage that affect the quality of that freedom in the real world. By teaching at Oxford, Finnis comes into contact with students and staff who are part of the groups he dehumanises. If a professor who is known for the above argument concerning homosexuality and evil teaches a seminar, it’s not ridiculous to suggest that LGBTQ+ students may be intimidated, stop contributing and learn less effectively.

At this point, “academic freedom” seems to be a label that some academics use when they don’t want to address these underlying issues. Glossing over them – by labelling counter-positions “ludicrous” and “preposterous”, as some professors have labelled our petition – shuts down discussion in exactly the way that critics allege “snowflake” students do.

What about the argument that even if Finnis’s views are discriminatory, they are permissible because he hasn’t said them to particular gay students in his seminars (as far as we know)? We think this misunderstands the nature of discrimination. When Finnis writes or talks about homosexuality and evil, or draws comparisons with bestiality, he is targeting LGBTQ+ students and staff. When Finnis is writing about a group, he is necessarily writing about its constituent members. Now, we accept that harassment can encompass more direct forms of discrimination, those arising in smaller scale, person-to-person interactions. But it does not follow from this that Finnis’s discrimination should be permitted because it takes place on a larger scale. We do not accept that more generalised (and more public) forms of discrimination do less damage.

The desire that discrimination be understood more accurately is what drives our call for policy change. We have seen academics defend Finnis online, in part, by appealing to how kind and gracious a person he is. Oxford University, meanwhile, responded that “vigorous academic debate does not amount to harassment when conducted respectfully and without violating the dignity of others”. Let’s clarify this.

In a seminar, if Finnis were to call being gay “evil” or liken it to bestiality, would that be done respectfully and without violating gay students’ dignity? The obvious answer is no. What about if Finnis says it politely and in suitably intellectual language – would it then be OK? We think the answer is still no. Those who argue otherwise seem to care more about the way people say things than the content of what they say. Such “respectability” arguments allow academics to hide behind intellectual language. If an employee at your local shop can be sacked for using discriminatory slurs, why should academics be able to get away with it because they use longer words?

The final objection to the petition is made on the grounds of religious freedom. This raises questions about how universities should address the promotion of religious views that say LGBTQ+ people are morally bad or inferior.

We think religious diversity is essential to academia. We also think that religion shouldn’t be used as an excuse to call LGBTQ+ people “evil” or suggest that it is “destructive”. Clearly, there is an ongoing conflict of views; the courts have been working out how religion and sexual orientation (both protected under the Equality Act 2010) interact. But critics – and Oxford University itself – do themselves no favours by ignoring this conflict. The petition takes a stance on this issue. Universities and academics should take a stance, too.

• Alex Benn and Daniel Taylor are postgraduate students in law at the University of Oxford