I haven't the slightest idea who Comey supported. I know Comey became a Democratic Party hero when he exonerated or at least refused to charge Hillary over her E-Mails. Then The Republicans wanted him fired.
Then a couple of weeks prior to the election, Comey reopened the investigation. Now he was a Republican Hero with the Democrats wanting him fired.
Finally when Trump fired Comey, he went back to being a Democratic Party hero. Go figure. Or perhaps I should say that is politics as usual.
I think you've horribly misinterpreted this process. Here's my take: Comey is a principled, conservative, ambitious, lifelong government servant who did a really, really stupid thing. And he did it in violation of DoJ rules for what he thought we're good reasons. When he had the first press conference, he had good intentions of protecting his institution (and himself) from criticism, but it was wrong - it interjected his personal conclusions into the public sphere over the interests of the institution. When he made the October announcement, he compounded the error exponentially. He f'd up, big time and gifted is the worst President ever.
In short, he was no one's "hero", but was "useful" in different ways, for different purposes for each party's interests. Then, in typical Trump fashion, he was shat upon for the most unprincipled reason possible, obviating all of that utility.