No one is treating it as fact, we are treating the "source" and/or reasoning behind the rumor as the bullshit that it is. Assuming of course that the youtuber is the same one I saw before that ends his reasoning with the whole thing being part of Disney's "FEMINSTA agenda", or however he put it, to push the female superiority over male counterparts or whatever.
The whole thing fits in firmly with that whole anti-Brie campaign that happened just before Capt Marvel came out.
I even saw another article on one of those click sites that stated "actors who are no longer working for Marvel" with a Brie Larson picture front and center. I didn't even bother giving them the clicks they didn't deserve.
It's not a rumor, it's not something they heard, it's an agenda they are trying to push. and wegotthiscovered has been known to just repost bullshit and/or seemingly make it up for quite some time. their track record is quite poor according to those that have been paying attention, and based on the past few "scoops" I've seen from them, none of them I can remember have come close to panning out.