The alternative may well have been a dead VP, or worse, so be happy that these channels exist(ed). With that whole department axed we are now in much more dangerous territory. That said I'm pretty sure that Elon Musk knows which side his bread is buttered on and that given an appropriately worded request Twitter will comply just like it did in the past. Or do you think they'll give the FBI the finger now?
You could. But that's not what happened here, judging by the evidence on display.
All I see is what I expected to see: law enforcement engaging in a careful manner with a company that is dealing with an extremely large flow of communications. And if some of those communications are of a society destabilizing nature it is well within the mandate of the FBI to stick their noses in and make requests. You then have the option to refuse those requests, in which case you may either end up in court, they could forget about the whole thing or you are served with a piece of paper signed off by a judge.
What is illegal and what isn't is ultimately for a judge to decide but not every two-bit issue needs to go by a judge if all parties agree that the world is better off with moderating it out of existence.