Do note that the clause you quote applies only to patent assertions. This means that your patent license is revoked if you bring a patent action against Faceboo

Do note that the clause you quote applies only to patent assertions. This means that your patent license is revoked if you bring a patent action against Facebook (or if you sure someone else for using React), but not if e.g. you sue them for infringing your copyright, or any other matter. This does seem like it would be a standard clause for any patent agreement with another party, but IANAL.