I'm not a lawyer so I won't try to paraphrase the license -- I actually think the wording is pretty simple already -- but to be clear, only the patent grant might terminate if you were to sue Facebook; the BSD license that the code is provided under remains valid regardless.
The author's claim that Google and Microsoft employees are unable to use React is false. I know there are teams at both companies using React and React Native. (It is true that Google was not happy with an older version of the patent grant, but we updated it in response to their feedback.)
If you work for a software company and your company has patents then keep in mind that by using React you are giving Facebook a free license to your entire patent portfolio.
More info on weak vs strong retaliation clauses: http://www.rosenlaw.com/lj9.htm
That contradicts everything I've ever heard on the subject. Can you cite any legal precedent?
Now, there's a theory that looks like this: The BSD license gives you a license to use a project. If I release some code under a BSD license, but I also patent it, and you download it, start to use it, and I sue you, then you couldn't really use it, could you?
So some people have argued that the "use" part of the BSD license includes all the rights needed to actually use the project, including the right to use any patents the author may have. There are some counterarguments too of course.
However, no court has ever considered the question, and no rulings have been made in either direction. Some day, a court may decide that the BSD license includes an implcit grant...or not. We'll have to wait and see.
Now, a followup question is: What happens if a court decides the BSD license includes an implicit grant, but an explicit grant is also included? Some people think that the explicit grant might replace the implicit grant; others think that it might add to the implicit grant. And if the explicit grant is seen as replacing the implicit grant, and the explicit grant terminates in conditions where the BSD license does not, then the explicit grant actually weakens the BSD license. Alternatively, if the grant is additive (or no implicit grant exists), then the explicit grant does not weaken the BSD license.
Petilon's position is right if: 1) A court rules that the BSD license contains an implicit grant and 2) Further rules that the explicit grant included in the React project replaces and extinguishes the implicit grant included in BSD license. So far neither step has occurred, but they might. In theory. :)