whats the point of outing somebody as a fellow trans person?

Idk maybe this is my fault for bad opsec but im genuinely infuriated

I have an alt where I’m not out as trans and I say I’m cisf. This is because I firsthand know what it’s like to be treated differently when people know you’re trans and now I’m post ffs and semi stealth ish I want to move away from being seen as trans

Somebody recognised me bc of my pics and said “lol everyone on trans subreddits knows who you are, why are you doing this? Stop pretending to be cis”

Like… what? Am I right to be pissed off? Especially bc I am not a Reddit celebrity by any means and most ppl on that particular subreddit would not recognise me. What is the point of this? If somebody clearly does not want to be perceived as trans why out then?