When I work for a company, I don't spin-off that company using corporate knowledge, I just find something else to do (and that's probably why I'm not rich :D), but it's the most elegant thing to do.
Zuckerberg is a famous example of such behaviour.
I think this Radon is talented too (good tech + doesn't wait for others to give permission + very interesting ideas), and what he did is probably okay-ish, a bit borderline but still on the ok-side (he seems more like a fan of Repl.it than anything).
I just wouldn't go til the point where I complain about it publicly.