I recognise that you have self awareness and praise your willingness to take accountability for the times you may talk out of line. I also understand that you have made some attempts to understand OP, which shows some level of sympathy towards his circumstances.

That being said

Honestly in the attitude you have of not "owing him the emotional labour" you are intentionally and deliberately announcing you don't want to empathise with OP and specifically because you want to advocate for trans women.

These things aren't necessarily mutually exclusive, you just don't seem to want to show empathy presumably because of your political intolerance of men.

You most definitely were taking a political angle in the remarks against OP as evidenced by attacks on privilege. You are sexist in implying, expecting certain things from OP specifically because of his political class (being a straight male) and privilege while talking down to him and judging him based on these political qualities.

It is reasonable to assume that you foresaw the probability that leaving judgements of OP's character based on privilege and announcing you do not feel obligated to care about him or show empathy, would or could be perceived in a way that hurts or personally attacks OP.

I would say further that this conduct demonstrates a lack of respect for the OP. And without respect, what merit is there in engaging with the OP's post other than for your own gratification?

You are free to advocate for trans women but this does not justify or excuse your disrespect towards men.

Though it isnt a requirement to empathise or be kind, it may be inconsistent to the purposes of the subreddit to deliberately announce you don't want to empathise with the OP and feel the need to judge the OP on arbitrary qualities he couldn't control. You provided some validation perhaps. But was it worth the immense judgement and personal attacks?

It is better not to leave comments that are incensed or judgemental, especially in a space for very vulnerable individuals. It should be reasonable enough that this subreddit should be a safe space for people to explore their emotions without fear of censure for being a certain way.