I made this library a while ago, long before all this hype about React's license (which was with the questionable clause from the beginning). I added support for Preact as I liked the minimalistic style of Preact, used it in my own projects and Jason was really responsive solving Preact's compatibility issues. Later on, Dominic asked if I want to add support for Inferno, which I did. I really love that there are different library implementations with compatible API, so you can choose a proper solution based on its pros/cons.