It doesn't require any sympathy or empathy, nor does it require any level of siding with her.

Either one believes that trans people should be treated equally before the law, or one does not. Ditto every other category of person. It is possible to have prisons which contain prisoners without exposing them to actual harm, and this should be true in every prison for every prisoner, no matter how heinous their actions.

So though women's prisons in the US are hardly free from both sexual and transphobic violence, nor men's prisons safe environments for male prisoners, sending a woman to a men's prison automatically makes her sentence far more onerous than that of her fellow insurrectionists found guilty of a similar level of behaviour but who are sent to prisons which match their gender. Remember; all of them are at least as supportive as she is of a party which endangers trans people.