I agree with the post. It's coded derogatory speech while being technically correct. Personally, I would go as far to say it's a dog-whistle and is absolutely a flag, especially if it renders any speech clunky and labored, or side-steps a person's gender transition status.

Also, here's something I've observed that may be relevant.

IMO, most of the time people use gender when telling a story, it's not relevant information in the first place. In light of recent events, public awareness, and politics, non-gendered speech (in English at least) is automatically the most inclusive way to go and it's a good habit to develop. The exceptions here are where it's information that supports the story, disambiguates complicated situations (e.g. talking about a drag persona), or where it's gender affirming in some way (e.g. respecting pronoun preferences).

I see this happen a lot, especially where woman/female is used as extra information when expressing anger, frustration, and disgust. For example, I hear "this woman cut me off in traffic" far more than "this man cut me off in traffic", with "this person" or "a BMW driver" as a maybe-neutral-but-also-likely-male coded qualifier. To me, it suggests a kind of negative bias for gender, which may or may not be unconscious (depends on the person). It may seem like a small thing, but it's freaking everywhere and it's gotta stop.

For the rare occasion where sex or gender supports the story, "my teacher, who is a woman, ..." or "my teacher, (s)he..." does the job. Yeah, it's is a bit tougher on the tongue, but you should only need to say it once for the whole telling.