My point was not about the details, but about the uncertain nature of an open source project driven by a company. The patent issue is just one of the "symptoms" of this problem. When someone open sources their technology and adds a set of detailed clauses that adds some restriction (doesn't matter if it's a "real" restriction or not), it means they couldn't go all out. It also means as a user, you do have reasons to be cautious about it, not because of what the license says in detail, but because of the reason behind the behavior.
But anyway, this patent issue is just one part of the larger issue, which is uncertainty. When Apple or Android changes the API policy in the future, you'll be struggling to adapt to the new reality with what you have. Sometimes it works, but sometimes it doesn't. Currently it does make sense for some people to build using react native, but if I were you, I would rather learn Android. Really, if you already have iOS experience, a lot of the paradigm is pretty similar and it won't be super difficult to learn.
This "cross platform" concept used to be valuable maybe in 2010 when it wasn't clear what mobile platforms would be dominant (with windows phones, blackberries, and even samsung launching their own developer platforms). But it's 2016 now, and we're pretty sure it's either iOS or Android. All you need is just those two platforms.