Note that WordPress is ditching React not because they believe there's any problem with React's license and patent grant, but because they think their users will be confused and angry . In other words, the baseless and meritless outcry about a perfectly OK patent grant caused this, not the patent grant itself. The subject became taboo, like female nipples in America, and WordPress doesn't want anything to do with the…
What an ironic statement, considering that that combination can be lethal to a company.
Besides, have you ever heard anyone say why they prefer to use Facebook even when they are aware that it is tracking their every move? Usually the answer is "convenience". By the same token, not getting confused or angry is also a great convenience to the user. Very few Wordpress users actually care about the baselessness or meritlessness of using one JavaScript library over another. They just want Wordpress to work.