We need to have a person of faith lead the country.
A. Candidate:
We need to have a Protestant lead the country.
In the first instance, Romney is (probably correctly) assuming that he'll gain more from "people of faith" than he'll lose from the critical atheist vote which he was unlikely to nab anyway. A. Candidate probably said a really stupid thing, because he just pissed off a bunch of catholics and others for unlikely political gain. Still, one can imagine how the press would treat these things differently. In the Romney case it's highly unlikely that the "did he piss off the atheists" question would even come up, and even if it did it is highly unlikely that it would framed as an issue of bigotry/intolerance.
However, in the case of A. Candidate the charge of "anti-catholic bigotry" would be front and center, and William Donohue would be on all 3 cable networks simultaneously for the next 90 days.
I don't advise A. Candidate, or any politician, to say things which offend a sizeable chunk of their potential voters, but much as it's perfectly fine for Romney to say that he doesn't want an atheist to be president, it should be fine for A. Candidate to say he doesn't want a catholic to be president. "Fine" doesn't mean "incredibly smart." "Fine" means not necessarily bigoted.