Replace "fandoms" for "corporations" and/or "big studios", and it makes a lot more sense.

Way to many times in recent memory their solution to a creating a "strong female character" is just giving her overpowered abilities… and that's it. Zero personality, backstory, personal goals, quirks, character flaws or anything that would make her interesting besides her powers/competence.

Pretty good point. Most of the people calling for "strong female characters" tend not to talk much about characterization and writing, thus resulting in the current large wave of Mary Sue's 

Also, VPhantom here is correct. "Fandom" is not a good label here since most of the people going insane about strong female characters are not really fans but rather online pseudo-progressive brainrot addicts.