...and how mainstream feminists are complicit in this.

idk why they're called TERFs. I don't understand the "Radical" part because they're right-wing reactionaries. I don't understand the "Feminist" part because everyone who calls them that agrees that they're not really feminists. I don't understand the "Trans-Exclusionary" part because they don't want to exclude trans women. They want to murder us. Or see us executed / driven out of existence via suspiciously unspecified means.

Also, TERFs don't hate "trans-identified males" (which is what they call trans women) for the "trans-identified" part. They hate them for the "male" part. They hate us because they see anyone with a penis (or who was "taught male behavior" growing up) as a dangerous potential rapist. They're not "trans-exclusionary radical feminists". They're misandrist bigots. Their transphobia is nothing more than a logical extension of the misandry/androphobia that has become normalized in more "mainstream" feminist communities. If "TERFs" hate trans women more than they hate cis men, it's only because trans women are more likely to try to enter "women's spaces".

But admitting that misandry a) exists and b) causes real, measurable harm to a group of people they claim to be allies to would be politically inconvenient for feminists. They'd have to actually stop and think about the harm their actions might cause, the way their actions perpetuate "patriarchal" prejudices - you know, the thing they're constantly telling men to do? - instead of indiscriminately bullying and harassing people and then hiding behind "activism" as a shield. So they ignore the root of the problem and focus on one specific aspect of it that doesn't require any critical thinking or personal growth on their part.

The similar acronym "SWERF" (Sex-Worker Exclusionary Radical Feminist) serves the same purpose of hiding classism/racism in the feminist community behind an issue that creates less political inconvenience. "Support sex workers!" plays a lot better than "Hey white women, check your fucking privilege."

TL;DR: By choosing to engage in, defend, or ignore androphobia within their communities, feminists are causing real harm to cis men, but even more harm to trans men and women.