To counter your point, you might remember the React team's about face when probably their largest benefactor in terms of free goodwill, Wordpress, threatened to drop ReactJS for its ambiguous license. I would think it matters a lot to FB right now that they don't do anything remotely annoying to the community.

I would be willing to bet that if Facebook adopted an attitude of "screw it, lets just stop responding to these idiots" that will make even fewer people want to work at Facebook right now, given all the bad press these days. I bet if you ask people why they are still continuing at Facebook these days, a fair number would say something like "Yeah, at least I can work on open source projects".

If anyone at Facebook reading this wants to go for a dare, why don't you try dropping support for a high profile open source project like ReactJS and see if that affects the candidates entering your pipeline.