Huntsman ran out of money and staked everything on doing well in the New Hampshire primary... which he did okay in, but not enough to keep at it. What exactly did you expect? Given that Huntsman was going to stop running, pretty much all members of the party are going to be expected to "endorse" and speak nice things about whoever the candidate is. Why not gain a few points with Romney and endorse now? (Okay, if he thought somebody else might win, you can argue he should endorse them, but seriously, from a left perspective, you'd surely lose *more* respect for a Gingrich or Santorum endorsement.) I consider being a good politician an asset, largely, so yeah, not blaming him at all for that.
I hope that Huntsman doesn't lose all his stock among Republicans, and this will help keep him a "good Republican." (Since I'd be fine with him being, say, president in 2016 if the Democrats nominate a lamer then, assuming Obama defeats Romney in 2012. Alternatively, if Romney wins, there are certainly worse people to stick in the Cabinet than Huntsman.)