Of the 10M+ react or graphql projects in the world, how many can you list that have had their patents taken over by facebook?
Folks will worry about facebook’s README.md clause but not buy a lottery ticket becuase they feel the odds are way too low. Go figure.
Also, writing down a legal clause in a github repo README.md, and having a judge actually rule in your favor (you being facebook), are two different things. I doubt any judge is going to hand your biotechnology patent library over to facebook becuase you used react to build your login form, or you made an HTTP request with graphql.
If facebook ever did sue you, airbnb and walmart would probably pay your legal fees to make sure the final decsion destroyed precedence for facebooks stupid little clause.