@HeavyMetalLover - I understand your point that the flippant use of sis and girl is not equivalent to misgendering a person. However, it’s still valid to express discomfort when a label or pronoun makes you seem uncomfortable for whatever reason. My ex, who is very gay, was actually also triggered by being called sis or girl. The reasons aren’t really relevant. We can all make good-faith efforts on behalf of others. We’re not going to assign WPs for something that most here wouldn’t think is offensive, but at the same time if someone tells you a pronoun or label isn’t for them, that should be respected.
I know you found his opinion to be unfair and the response to be rude (I disagree, personally) - but he prefaced his opinion with a warning and immediately apologized if others found it offensive. Sometimes we get triggered and get so upset we lash out and feed the anger instead of taking a breath and switching to discourse and kindness.
We’re all on the same team, like how I allow Fun Tonight haters to stay on the site.