I would ask the Democrats here just how they would have felt if in 1976 the Democrats nominated a Democrat who, explicitly, refused to endorse George McGovern in 1972. (Jimmy Carter was, certainly, a guy who tried to stop McGovern and didn't campaign for him, but he DID endorse him to the point of saying he would vote for him.) Would they have been OK with, say, former Sen. William Spong (D-VA), a moderate who, nonetheless, never even said that he'd vote for McGovern? Would they have been OK with Gov. Mike O'Callaghan (D-NV) who refused to endorse McGovern?
There have, over the years, been lots of Democrats who were LOCAL Democrats, but not NATIONAL Democrats. Most, but not all, were from the South and Border states. Is it OK for a political party's national chair to reward folks who bolt the ticket? How does that play with folks who are loyal, despite some distaste for the nominee?
The distaste for Trump from many Republicans is all issue-based. They are globalist-interventionists, and Trump represents a departure from both, as well as a hostile takeover of the GOP's Presidential nominating apparatus. It has nothing to do with "temperament", or any of that crap; that's just an excuse, albeit one Trump has sometimes provided. It's no different than Democrats for Nixon, or those Democrats who wouldn't endorse Mondale.
And I'll say this: History has never shown good things happening for party bolters. Ever. Show me one bolter who went on to prominence in his own party. The ones that did almost always had to switch.
Nobody is proposing that defectors are "rewarded". If the voters don't like this, then the candidates will feel the consequences on their own. On the other hand, if these people are successful in the future, then this sends a strong signal that Trump was a bad idea, which is just what the GOP needs to avoid becoming a caricature of itself.