That's how Apache 2.0 and GPLv3 treat patents. The language in the React license is not symmetric like the above licenses and thus doesn't feel like it's a "screw you" to patents. Not to mention that Facebook is very patent-heavy and it doesn't feel like they're anti-patent in any meaningful way.
I'd be more sympathetic to Facebook if they declared they would never use patents to sue someone and they'd only use their patents "defensively". Of course, they'd never do such a thing even though such a statement has zero weight.
