Does the American electorate have a distaste for plainspokenness?

[Phony Moderate]

Barack Obama, Ted Cruz, Scott Walker, Hillary Clinton. All four of these have policies/viewpoints that may very well offend large sections of the populace, but all four have relatively goody-good personalities. Rarely any color in their language whatsoever. To state the obvious, the first is the incumbent President and other three are all regarded as serious contenders in the race to succeed the first.

Allen West, Alan Grayson, Howard Dean and Michele Bachmann. All four of these have viewpoints that, if you read between the lines, are not too different from (or identical to) that of the mainstream of their respective parties (and Dean was of course the chairman of his party). All four of these have a common problem: their mouths. Due to their plainspokenness, they are dismissed as lunatics/buffoons/extremists/some combination of the above. If these four had the personalities of the four listed in the previous paragraph, they may all have more prestigious jobs and would be serious contenders for the Presidency in 2016.

In my nation, we have a fellow by the name of Boris Johnson. He often uses provocative language, such as suggesting that those with sub-par IQs are worthless. However, he is well-liked, seen as perfectly mainstream and has a realistic chance at becoming Prime Minister. Conversely, the three main party leaders are all pretty loathed. But their personalities are more in line with those in the first paragraph.

So, what be the answer to the title question? And if it's yes, then why?