React makes me sad because the PATENTS file means I can't sell my creation to anyone suing Facebook for patent infringement. Personally, I don't think that software should be patentable, but it is and deep pocketed companies are always suing each other over this and other IP. Even if they aren't today, there is no guarantee that they won't tomorrow. So why bother with a technology that pisses in the proverbial pool, especially one full of lawyers (aka deal killers)?