I dislike when people like RMS get semantic and gatekeep words like "free software", but this is the end product of a world without gatekeepers. People just use words in a way that's convenient to them.
Or maybe some gatekeeping is actually good, and we just have to use more of our braincells and figure if a particular gatekeeper is good or bad. It's a good thing that being a pilot for an airline is gatekept to qualified pilots that know how to fly a plane. It's a bad thing that I need a hair cutting license to buy hair dye to dye my own hair at home.
We often see semantic drift over a long period of time. It's just that the overarching topic of AI is being played significantly faster than what we would normally have observed in other fields.
Why? Prescriptivist/prescriptivism is afaik the usual term. Proscriptivist is the other, but quite rare, so rare that my phone dictionary says it’s a misspelling.