I think it is partly pure machismo on his part - attack the perceived enemy but in a way they believe you never did or cannot respond plus your social circle will not see it as an offence. His post about transness had a lot of 'but I'm so much more macho than other men!' along with him writing about any queer topics or his looks (anything about his style had an addon of how stereotypical he is). The guys in question could have been ... too confident, not vulnerable enough or whatever else he seen as danger.