He doesn’t own all of TSLA, so if there’s no contract, he’s appropriating TSLA to his private project. If it was done off the books, it’s syphoning money from something you don’t own to something you do.
You are taking as gospel a uncorroborated rumor from what is likely a single Twitter engineer who is salty that someone outside the org is reviewing their code.
You assume that money is not changing hands and that it’s off the books? Where is your evidence for that? You are making that assumption based off your own confirmation biases.