Republicans hate Obama more than they ever hated Kerry or Clinton.
Clinton was a bit more moderate and Kerry did not win.
Look at what happened when Crist hugged Obama. Now Christie has done that, and beyond. Even seeming to side with Obama while snubbing Romney in the last few weeks of the election. And continuing to support Obama and attack other Republicans.
You have no idea how bland of a Governor Charlie Crist was. Unless he ran for Governor again in 2010, he had no chance of winning any Republican primary, with or without the Obama hug. A better example is the owner of Big Apple Pizza in Fort Pierce, who picked Obama off his feet when he went to hug him, and lost a good deal of business.
In a sane country, this shouldn't hurt Christie. But it really has. He has stronger approval ratings from Democrats... who will easily be persuaded to vote Democrat again if Christie ever makes it to be nominee (which he won't, unless the GOP radically transforms by Election Day 2016).
Again, people over estimate Christie's "problem" in the GOP. Come 2016, when he is the only electable candidate, the base and establishment will rally around him.