When I met him, Bay struck me as ridiculously charismatic (more so than basically any other actor/director/producer/what-have-you I've met), but he also seems like someone who falters in situations where he's not the center of attention. To his credit, he was fairly open about having a deep lack of self-confidence before he became a famous director. (And, furthermore, he IS the nerdy male lead in all his movies, though I think he also sees himself as the badass supporting character--and all his movies have these same character types, who are in some way unified at each of his films' respective conclusions.) But anyhow, I could certainly see him being increasingly awkward as he talks with fewer and fewer people on an increasingly less-anonymous and less Michael Bay-centric basis so I'll believe some of this.
As for the "almost killed them" part, Bay was pretty proud of putting Shia on top of the high scaffolding on Transformers, and he brags about all the expensive equipment he destroys and the dangers of his work. So I'll believe some of that.
But, really, these two have been at odds in the press since forever, likely because they have the same sort of "me-centric" worldview and they resent each other's successes and reputations. And the whole "Hitler"/"Napoleon" thing is just hilarious, stupid, and unduly mean. (Bay's tall and claims to be biologically part Jewish, which makes the comparison even funnier.) I can't wait for what Bay says in response, though. For what it's worth (next to nothing), I quite liked Bay, but I can imagine he's hard to work for.