1) I think that Santorum is correct to challenge the idea that we should encourage everyone to go to college, for reasons explained here.
2) While I have seen no polling on the question, I suspect that Vice President Biden is also correct to suggest that this idea is held by most Americans.
3) I see no reason to believe that President Obama promotes this idea because he looks down on people who do not have college degrees or wants to get more people to go to college so that they will lose their religious faith; certainly I do not believe that most people who accept this idea do so for any such reason. (It should be noted, though, that false accusations of snobbery are more frequently leveled against people on Santorum’s side of the debate by people on Biden’s. The claim is that we think college should be reserved for an elite and everyone else denied its benefits.)
4) Biden’s argument that more people should go to college because college graduates make more money than non-grads is a non sequitur. It could be that college graduates as a population have different characteristics than non-graduates (higher IQ, notably) and that these characteristics, rather than the degrees, account for much of the apparent wage premium. It may also be that we could pursue reforms that would reduce this premium by making it easier for non-grads to get higher-paying jobs. (I have in mind, for example, Charles Murray’s proposal in Real Education for the development of competency tests in various fields of employment as a substitute credential.) Or both of these things might be true.
5) Santorum deserves credit for challenging a false idea, but deserves blame for doing so in a way that is easy to dismiss.