It's funny, I just stumbled across the post and thought exactly the same thing. I've posted a somewhat lengthy response in the Reddit thread, copied below. The only advice I could give to the younger members here is stay strong and stand your ground; this conversation has gone mainstream and the majority of people are on your side. People are waking up to it; there's a lot of pushback in that thread alone.

From my Reddit post:

Educate myself? Good lord, the arrogance. Right up front, we do need spaces for “cis” gay, lesbian and bisexual people. Anybody denying provisions for that is either very young or has nefarious motives IMO. I consider your title more of a Freudian slip.

Some background…

I come from a small and moderately socially conservative, western country, a country that could be a lot worse, but still has one foot stuck in the past. I’ve been out for about 17 years now and around that time I fell madly in love with another guy. I consider myself very fortunate in that I had/have supportive parents, but my boyfriend sadly wasn’t so lucky. His parents were next-level homophobic, the kind that you read about in the news from the worst excesses of religious conservatism. Over a period of about 24 months, he was threatened with excommunication, castration, forced transition (the logic being that this would make him “straight”) etc. You get the picture. Rather than endure that, he moved in with me. The first 8 months were great, but beyond that, I could tell that the weight of excommunication was really starting to affect him.

We talked about it a lot, attended some support groups, anything and everything. Conversation would be continually dominated by the trans individuals there, each and every time. They never shut the fuck up, frankly. Too many voices, too many wildly different experiences for it to be constructive. You see, for my partner, transition was used a threat. It was completely inappropriate to be sharing an emotional space with people who intentionally do so.

Over the next few weeks he went into quick decline and ultimately, I would return from work one afternoon to find him hanging from a pull-up bar. To this day I still carry guilt about it and, in truth, I never really got over it. I loved him. My partner needed these spaces. My partner needed to know that his experience wasn’t unique. Would it have made a difference? Maybe, maybe not. Fundamentally, the blame lies with his parents, but the fact is that the support he needed became “unfashionable” around that time. He was sidelined. They were suddenly all LGB+T spaces, and it was all downhill from there IMO.

If you can’t understand why these spaces really ought to be separate, it’s because you lack the experience to know why. Anybody championing their mass culling ought to be ashamed of themselves. You have no idea what you’re doing, the damage you’re causing and, frankly, many of us “cis” people – a fatuous term but it serves a purpose here – are fucking sick of it. To now see us described as “genital fetishists” with disturbing frequency, is just the icing on the shit sundae being served.

You do you, let us do us. I’ll continue to support trans people however I can. I really will, just as I have done in the past. But I’ve gotta be honest with you, the path that you (and trans activism in general) are currently taking is nothing short of a betrayal...and it’s going to bite you in the ass, politically.