I don't think the American public like Romney much, either. He fits neatly into two stereotypes we typically revile:
1) In business, he made an absurdly large fortune being the outsider corporate strongman who came into a company, reworked things, fired a bunch of people, and moved on. Investors may like those sorts of people, but the vast majority of the populace hates that archetype.
2) In politics, he's that most reviled of creatures, the flip-flopper. He'll say anything that he thinks will get him ahead. He's been documented doing it over and over and over and over again.
It speaks volumes of the right's hatred of Obama that they appear to be so behind a man like Romney who would otherwise be pretty handily booed off the stage. I find it amusing to think that the right would be as supportive regardless of the candidate, whether it were Gingrich, Perry, Cain, or even Bachmann. Ron Paul wouldn't ever be allowed to hold the candidacy, of course, because he's not pliable enough.