It’s not shaming to say someone is against trans people nor is it disparaging unless someone is bringing politics and moralism into it. Like I said I don’t want even more gender politics from the other “side” as some kind of “backlash” journalistic piece. It’s all a wash of nonsense.
It's a disparaging remark to make it clear that the other person's opinions are wrong and that they as a person is of lesser value and should be ignored or attacked. It's used as a conversation stopper and to polarize the discussion, i.e. rally support from like minded and suppress the other party.
It's also not used merely to say that someone is against trans people, like you suggest. It's used by a toxic community that are immune to nuance and opposed to debate other than to force their own view on everyone else. Very few people are against trans people, but maybe some doesn't buy all of the identity politics. Saying that women menstruate is enough to be labeled a terf by the online mob. There's also rarely any radical feminism expressed by the people being labeled as terfs.
