They were there because they share the Nazi's view that women (in the original female meaning) who consider the social and physical consequences of being female significant enough to justify their being recognised as different to, and at times physically separate from, male people, and who want, as a historically oppressed and marginalised group, to retain the historic name and rights of their group, are inescapably, inherently anti-trans simply by the act of differentating between physical femalehood and a gender identity of woman.
Yes, the nazis were there because they agree with this imagined anti-trans position while Antifa were there because they disagree. However, underpinning these on-the-surface opposite views is the same fundamental delusion.
So in this matter, Antifa, TRAs and nazis are all wrong.
Because recognising the social and political validity of female people to a social, political and legal existence is not an act of hate against trans people. It is simply the recognition that female people do exist, and sometimes that matters more than a trans woman's identity.