If it's anything like the bigcorps where some of my friends work, or even medium sized companies where I've worked in the past: The patent clause is the React

If it's anything like the bigcorps where some of my friends work, or even medium sized companies where I've worked in the past: The patent clause is the React license probably isn't a problem. Probably. But in a conservative bigcorp, probably isn't good enough. If you're a decision maker, you want to be certain. You want this certainly because you have to cover your ass, because it's your ass that's on the line on the off chance it becomes a problem. Or even if you end up under a manager who dislikes you for some reason, or no reason at all - they might see the license, and question your judgement for exposing the company to potential liability. Or maybe they don't even dislike you, but decide that questioning you would be a good power play that would make them look good to their superiors. So if you wanted to use React, you have to clear it with the legal department first. And if you're at the kind of bigcorp when you've ended up in this situation, you're at the kind of bigcorp where clearing something like this with legal is a bigger pain than it's worth. And so you just choose Angular, or Vue, or Aurelia. All of which will probably meet your needs. But the project will still fail because the department you're making the app for gave you terrible specs, and you made what they asked for instead of what they actually needed. So I'm not a lawyer, but that's a story about how that clause in the React license can be a problem even if it isn't a legal problem.