Yeah, I think we need to keep in mind that "welcome to the team" does not necessarily mean "pure as the driven snow."
Perhaps these allegations against Dershowitz are false, and there were repeated attempts to get some kind of dirt on him to make him controllable and he resisted. He has always been a staunch civil libertarian and these kind of public figures are an increasing problem for the Democrats…I get it.
Perhaps he has seen the light and reformed himself. If that's the case, godspeed to him.
Or (I think more likely)…he simply cut a deal to save his own ass.
In any case, welcome to the team, Alan.