I have said it before and I will say it again: if you can't win the primary, then you can't win the general election, either. That is why we have primaries.
If Republicans are going to be angry with anybody at this point, it's Nikki Haley. She should be bowing out, having lost her home state by 20 points. Yes, Trump has an unban/suburban problem, along with a plethora of other problems. He and the party need to get to work, and Haley staying in the race is counter-productive.
As Donald Rumsfeld said, you don't go to war with the army you wish you had, you go to war with the army you have. Trump is the army we have. So saddle up.