This is Facebook’s T&C if you are using React JS framework. To summarize:
If you use React, you cannot go against Facebook for any patent they hold. Full period.
So if you are a startup hoping for million dollars acquisition from large companies like Google, Amazon etc. hold on to your dreams.
Potential buyers will not touch you with a ten-foot pole, if buying you means they have to surrender their rights to ever sue Facebook for patent infringement.