Do you get angry at people for calling sea stars starfish? "They aren't fish they are echinoderms!"
Or perhaps you get angry at people who call light utility vehicles "trucks"?
Language evolves. People accept colloquial definitions. Wait until you learn about pencil lead, koala bears, dry cleaning, and peanuts. Windmill is absolutely acceptable if it's understood by people to mean wind turbine, which it is.
This is an interesting response.
I think you know that “windmill” isn’t just a synonym for wind turbine but a politicised insult originating in the fossil fuel lobby.