Earlier quoted context omitted.
Considering almost every single large tech company is using React, presumably there's not much reason for concern? IANAL. But you're not wrong, preact is a great alternative to react and it comes with a permissive license.
If you're concerned about React, then Preact is actually significantly worse. Consider: The risk for React is based on 1) speculation that Facebook has patents on core React concepts and 2) the fact that patent grant that comes with React terminates in some situations if you end up in conflict with Facebook. So for safety, it might be better to make sure you use code that Facebook has no patents on, which (if (1) abo…
Software interfaces cannot be patented - this has been upheld in every court, most recently in Google V Oracle.