I'm critical of an individual candidate, not a party. I was critical of him before he won his nomination.
As for the people voting for him.......they're actively making sure their wants and needs are poorly represented. And that's on them.
I don't know too much about this race or Georgia politics in general, and I obviously can't speak for the Georgia voters. But here's my best guess.
The biggest portion of his "supporters" are going to be what Cincy said...that 80% of people registered to a party who are going to vote party affiliation no matter what. It's the same with the majority of voters who will not vote for him....both sides probably don't know and don't care about many, if any, issues, or his personal character. So expecting the needle to move a great deal without an earthquake by political standards isn't likely no matter what. For that 20% of people who will try to inform themselves or have an opinion which may make it possible for them to vote against their party affiliation:
First thing to consider is the alternative. If there is such a thing as the lesser of two evils, you could feel morally justified in trying to make sure the worst case doesn't occur, even if the alternative is also bad. In particular, I think Walker is running against Warnock (?? right? or not?), and there is probably a segment of voters who are thinking they'd take almost anybody over Warnock. So if a voter considers Warnock an unmitigated disaster, they may not like Walker but still vote for him. Exhibit A on a candidate being bad, but why people will still vote for them. This applies both ways, obviously. You could be a Democrat and really dislike a democratic candidate, but if the Republican alternative is the worst of the worst for how you'd like things to be done, you probably don't sway your vote just because "your" candidate sucks.
Second thing to consider is how people view "now" vs. "then." Megyn Kelly mentioned yesterday, I think, about how the new allegations that Herschel formerly paid for a woman pregnant with his child to have an abortion shows hypocrisy with his pro-life stance. Someone could
potentially disagree with that, although they may not. I'm not sure when this is alleged to have happened, but suppose it was a while back, one may reasonably believe that Herschel used to be okay with abortion but has changed his mind. Or that he was never okay with it yet acted wrongly according to his beliefs (hypocrisy), but would not behave that way anymore. Kelly's position--which is a popular one--assumes that people are one thing all their lives and never change their mind or act wrongly according to their own beliefs, and that simply isn't true. A voter who doesn't take that into account may agree with Kelly here (and thus be a voter who could swing away from supporting Walker), while a voter who does take it into account may continue to plan on voting for him. This applies to any issue and is only an example I'm using to try to get in the heads of potential voters.
A third thing to consider is how much people separate an office from the person holding it. It is possible to view leaders in positions of importance similar to, say, airline pilots.....given the choice we'd like our pilot to be friendly and moral as well as a great pilot. However, if given the choice between a pilot who is the nicest guy in the world and who is an okay pilot, vs. a guy who is an absolute and irredeemable a**hole but is a great pilot....we're taking the a**hole, because there are jobs and positions where ability to do the job is simply far more important than personal history in the minds of many. If I had to guess, there is a segment of the voting population who will overlook the personal behavior of a candidate as long as they think that candidate will act in their interest if elected. They may rather a candidate who is also nice and has no skeletons in the closet, but it's not irrational to overlook this in certain instances. I thought I'd seen that Walker is significantly behind Warnock in the race, but if it's close, Walker may really need that type of voter, because the video his son just put out is not a good look. And I'm told his son is very right-leaning. So when your own kid trashes you and warns people about you, that's a big blow as far as losing the segment of the voters who won't overlook personal conduct/history.