a) They couldn't. They tried unsuccessfully in previous cycles. It's a solidly blue district, and nobody wants to waste time on it.
b) They won't be grateful for his vote. Practically, he won't win anyway, but if he did he'd have to do it without any GOP support or money, and there is zero chance they'd let him caucus with the party.
c) There is no comparison to Trump or Moore. He's an actual Nazi.
d) People suggest the GOP are Nazis all the time. There is zero chance an obscure congressional candidate would get interviewed by CNN if he were running as a Democrat. He's being interviewed solely for the implication that he's connected to the GOP.
Moore:
1) said homosexuality should be illegal
2) said people should be barred from serving in Congress if they weren’t the right religion
3) said America was last “great” when slavery was present
4) stuck with the racist lie that Obama’s wasn’t born in the US
5) called Islam “a false religion”
6) furthered the lie that US communities are under sharia law
7) suggested the abolition of every amendment after the 10th
Called native Americans and Asian Americans “reds and yellows”
8) was credibly accused by multiple women of sexual assault and by one of making sexual advances towards her when she was a child.
And the GOP rallied round, raised funds for him, endorsed him... So I wouldn't hold much faith in what levels the party won't lower themselves to at the moment*.
The one thing that might make you correct is the very fact that he won't win that district. If it was a viable seat, I suspect the GOP's response would be significantly different
I say at the moment because the GOP wasn't always like this. It used to be a legitimate and sincere institution (albeit one I generally disagreed with in policy terms). They've gone completely off the rails over the last decade or so.