I am not a lawyer. My perspective on it is informed mainly through reading the thoughts of lawyers on this topic. But here goes.
A few weeks ago, a developer (who is not a lawyer) wrote a popular Medium article asserting that Facebook could use its BSD+ patents open source license - which is uses for React and some of its other open source libraries - to prevent you from suing them. So in theory, Facebook could compete directly with you and perhaps even misappropriate your intellectual property, and you wouldn't have good recourse.
Here's a link: medium.com/@raulk/if-youre-a-startup-you-should-nā¦
That article has some thoughtful responses from lawyers who make this sound a lot less scary than the original author made it sound.
Also, a former Facebook employee said that it's not nearly as bad as it sounds and it's just there so that Facebook doesn't have to have their legal team review every commit to their open source projects.
Again, I'm not a lawyer. freeCodeCamp.org uses React and Redux, and may use GraphQL and other tools in the future. We are not planning on suing Facebook any time soon (I imagine that would be quite an expensive feat for a small donor-supported nonprofit) so this clause doesn't seem to have any immediate impact for us.
My advice is if you're really worried about it, talk with an IP lawyer.