For one thing, it shows how weak the Republican candidates are. As ridiculous as Trump is, they make Trump look good.
Here's what Peggy Noonan has to say:
"His rise is not due to his supporters’ anger at government. It is a gesture of contempt for government, for the men and women in Congress, the White House, the agencies. It is precisely because people have lost their awe for the presidency that they imagine Mr. Trump as a viable president. American political establishment, take note: In the past 20 years you have turned America into a nation a third of whose people would make Donald Trump their president. Look on your wonders and despair.