Itronically, if anyone protested against transpeople with placards advocating their beheading or cannibalisation, they would be arrested, as gender identity is a protected characteristic and sex is not. AFAIK this has never happened though.
All that fact-based feminists on here are arguing for is that men should not be given female status, not that anything should be taken from transpeople. We keep being told that trans rights won't detract from women's rights, but if that is the case the same applies in reverse.
Opinions may vary, but for me, what this would mean in practice is that there would be men, women, transmen, transwomen and non-binary people, and everyone would continue to be segregated by sex in the situations where it is deemed necessary (most of the time there is no need for segregation at all).
Transmen and transwomen could live their lives as they wish, and at all times be legally protected from abuse and discrimination, as they are already.
The extra protection that transpeople enjoy under the Equality Act should remain, and making misogyny a crime under the Act should be reconsidered, as this would bring women into line with transwomen and give us the same rights when it comes to legal protection against hatred.
Human rights should continue to apply to all humans, as they do already.
Any 'marginalisation' should be clearly explained, so that it can be mitigated and we should work towards its elimination. Currently it is difficult to know how to prevent the marginalisation of transpeople as the term is so vague as to be meaningless.
Women should be able to feel safe by not allowing men in places where women may be vulnerable, and should have the chance to compete in their sex class in things like sport, where their biology makes it unfair for them to compete against men.
Social data should not be collected in such a way that policies and situations that disadvantage women are made obvious, by classifying people by sex and not so-called 'gender', as that obscures reality.
Finally, the language should be allowed to develop by custom and practice as it has done for millennia, and not legislated for with words and expressions being forced on people, legally or by social pressure.
What is unreasonable about any of that?