They were beyond the usual bitter

Most Leftists were deeply bitter about Trump winning beyond the usual bitter. They felt robbed. Articles that talk about it describe John McCain was extremely at Trump for beating Hillary. McCain's family would have shared this bitterness.

Your last sentence implies that it would have been beneficial to white hats to off him too,

No, I never said the White Hats offed him. What I was saying was the DS offing him wasn't something the WHs would shed a tear over.

The domain names are some big chunk of the whole scheme

McCain only ferried the fabricated data around to the press and other politicians. He was not the one involved into stealing or fabricating it. I wouldn't mix up who did what. He didn't personally do anything with the domain names.

Joffe and the Georgia Tech researchers did that. Micheal Sussman used their data to the make the white paper that he brought to the FBI and CIA. The domain names are with Joffe and the researchers.

How Q would know the date and time leads to a whole other area of comms. That's quite a rabbit hole in and of itself.