We haven't seen Twitter arbitrarily leak DMs yet. Even Matt Taibbi said they only have access to screenshots of admin interfaces directly related to their specific stories around uncritical FBI/DHS access, shadowbanning for questionable political purposes, and the whole Trump thing. It's far from the ideological free-for-all people are suggesting.
But Elon has already shown he's willing to play dangerous games with his power. So far we haven't seen the FUDy stuff yet beyond the stupid new doxxing rule for which he's burned tons of good will. Nothing comes without costs.
A hacker pulling off an exfiltration of the entire DB of any major tech company I'm very skeptical about that happening.