These same Republicans who are saying how they oppose Trump are the same ones who've been making it harder for ethnic minorities to vote, who oppose a woman's right to choose, who want to raise taxes on poor people and lower them on rich people, who oppose raising the minimum wage, and oppose full human rights for LGBT's, and take money from oil companies and deny that global warming is happening, etc.
Don't let them fool you. What they dislike about Trump is his complete lack of subtlety and tact about his plans to screw over everybody except rich white straight Republican men. The main difference between them and Trump, and also the reason that Trump did so much better in the GOP primaries than he's doing with the general voting public, is that they're a little bit sneakier about it.
Only a little bit.
Is Trump falling in the polls because of the Republicans distancing themselves from him, or are they distancing themselves from him because he's falling in the polls? I think it's the latter, and that the Republicans who distanced themselves from Trump earlier just had a hunch earlier that Trump was going to lose big.
Don't forget how much Obama's hands have been tied because he faces Republican majorities in Congress, and also among the country's Governors and city councils and so on. You like Hillary's policies better than Trump's? Then you need to vote for the rest of the Democrats too, not just for her, because all of us Democrats have pretty much all the same positions. (Bernie was never special and different. Never was, isn't now, never will be. Progressive politics are Democratic politics, and Bernie has only been a Democrat since 2015.)
You also need to vote more than just once every 4 years! Republicans are much better at getting to the polls in all of the elections in between the ones for President. That's why they have those majorities in Congress, and among the Governors and so forth. I'm starting to feel very optimistic about Hillary beating Trump, but Democrats need to win those other elections too. We need to get into the habit of showing up for every single election: primaries, Governors, mayors, judges, city councils, budget proposals. I know, it's a lot of work keeping track of all of those things. And all we would get for going to all that trouble is a completely different world.