The reason this hits home with Romney is two-fold.
First, Romney is saying the opposite of whatever Obama says unless it is superpolitically incorrect to do so, and he is so far managing to eek out of it.
Exhibit A: Romneycare versus Obamacare. Despite the fact that Romney clearly stated that the individual mandate was the key, and despite the fact that he said it should be done nationally, Romney has managed to throw up enough of a smoke screen to try to distinguish the two. Its crap, of course, but he managed to avoid getting tied to it.
Exhibit B: No bailout to the auto industry. Romney pretty clearly on record saying they ought to be allowed to go under. Problem is, it worked. And it worked in places like Michigan and Ohio, where electoral votes are at a premium. He is trying now to reframe and back off of his earlier remarks as saying it should have been some sort of "managed" bankruptcy, although he has yet to describe what that would have been like.
Exhibit C: Student loans. He said he was against keeping the interest rate low. Then one week later, he is for it. There's some wiggle room there he has been trying to use to get out of it. But its weak.
Exhibit D: bin Laden. Again, he just said the opposite of what Obama said at the time. Obama followed through on what he said, and so now we are left with "of course" he would have done the same when, the simple fact is, he said he wouldn't just so as to criticize Obama at the time.
This may ultimately be Romney's downfall. Its that he stands for nothing, really. And what he has stood for at some point in the past, he is willing to go back and parse words to try to keep from defending anything that in the current moment seems to hurt him.
Although our presidents over the last few decades have had differing degrees of resolve, and although we all take issue with what each was resolved to do, or was resolved about, they all at least had some degree of commitment to some thing, some ideal, some principle.
Romney just doesn't. And that is why support for him even within the GOP has been tepid and lacked enthusiasm. He can only run as the anti-Obama for so long. At some point, people are going to ask why he SHOULD be president, not simply why Obama shouldn't be.
As of now, anyway, he doesn't have an answer and, in fact, every time he offers one up someone can find him saying something pretty close to the opposite in the not too distant past.