Incorrect; all they can do is revoke your patent grant and then sue you for patent infringement. They can't "revoke your React license".
So the difference is, if you use React they can only sue you for patent infringement if you sue them first; if you use something else they can sue you no matter what...
...if they have a patent on React. Despite your breezy assertion, patents are public, people have looked, and none have been found.
Have you watched Wargames? The only winning move is not to play.
If you have code, you're at risk of being sued over software patents. In the end if you do get sued it likely won't be Google or Facebook, it will be some patent troll you've never heard of that randomly extorts companies into bankruptcy and can't be countersued because they're a non-practicing entity (i.e. they don't have code).
Maybe Facebook has patents for React. Maybe Facebook has patents for other libraries. Maybe other companies have patents for React. You won't find out until it's too late, so stop worrying.
It almost makes you wonder if startups should make a point of using react somewhere, even if it's just peripheral so as to be sure that they have a patent license for whatever frontend framework they are using.
I mean probably FB got patents.
and
Probably they have at least one that covers things React can do.
Almost every framework moved to components and virtual DOM.
So there is a big chance that any framework out there could infringe some of these React patents.
So their either can
revoke your React license when you sue them
or
Sue you over patent infringement if you don't use React