I realize that, which is why I avoid anything to do with transexuals on LW

If you were trying to avoid anything to do with it, why would you make transphobic comments apropos of nothing in unrelated discussions? That's either not trying very hard at all, or failing really spectacularly despite one's efforts. When I'm genuinely trying to avoid a topic -- as opposed to merely claim avoidance for signalling reasons while actually wantiing to broach it in conversation -- it doesn't tend to suddenly crop up in the most random of places, unbidden, in crowds that haven't been preselected for a willingness to hear it.