And this fellow has a plausible reason why:
Remember when Donald Trump was losing?
If you blinked, you might have missed it.
It started during last Thursday's debate, continued through the muddled results of Saturday's caucuses and primaries, and lasted until, oh, around the time that news outlets began calling Mississippi for Trump a few minutes after the polls closed in the state on Tuesday night.
Now that Trump's march to the nomination appears to be back on track with decisive victories in Michigan, Mississippi, and Hawaii, it's worth pausing for a moment to assess just what went wrong with the #NeverTrump movement. Why has it done so little to alter the shape of the race? How has Trump managed to stay on top through the unrelenting critical coverage of the past week?
A good part of the answer lies in the distinctive defects of the messengers. In just about every case, those leading the charge against Trump lack the credibility to make the kill....
http://www.theweek.com/articles/611489/how-gop-stupidly-enabled-donald-trump-comeback
tl;dr: the most prominent Republican figures leading the charge against Donald Trump are easy to describe as compromised in one way or another. Thus, because of their pasts, they end up playing into Mr. Trump's hands.
Exactly. As Trump himself put it; it´s not for everyone to be a scumbag...I guess he used a more polite word but the meaning is the same.