So we seem to be slowly narrowing it down to this:
Trump has been pushing back on all these investigations (1) because he’s got something to hide, or (2) because he’s a total nut-case and can’t control himself, just like Hamlet.
Someday, he may come to realize that he was wrong about this:
Just when he was pretty sure that it was safe to fire Comey because nobody had been investigating him for colluding with the Russians during his campaign, an investigation that Comey oversaw, he fired Comey — which, of course, got people starting to investigate him for firing the person who was overseeing the investigations of his campaign. He should have known, as most of us do, that just because you’ve never been accused of robbing a bank doesn’t give you license to go out and rob a bank.
In any event — not that it matters anymore but it's still nice to know for sure — but he’s certainly proved Hillary absolutely right when she claimed he was totally unfit for this job.