I think the hacker stole by deception and that is certainly theft.
My problem isn't collusion per se, but collusion at the behest of the Foundation. I don't think anybody believes their motives are as pure as the driven snow.
Foundation is dysfunctional. It lacks governance, it's full of factions. But the scheme behind this theft is probably more complex. Of course a certain faction could be a part of it. But following some trails, logs, public stances, Mircea, letters, timings, suggests that this was usual speculators game. There are many lies in truths in lies and so on, but ultimately all shows normal crypto world dirty tricks. Dressed in big words often.
Ethereum can be blamed for utter irresponsibility (especially certain people there) and inability to identify whom should they bribe first. Not for collusion per se. We live here in a very corrupted but funny world.