I think there are distinctions to be made between those whose sole claim to fame is fame itself, and those who do something concrete. I put the Beatles in the latter category. Paul Newman? Well, maybe for his salad dressing. Obama? I'm betting on him for particular reasons, not as a fan. He had plenty of opportunities to take a nosedive off the welcome wagon, in my view, and he was balanced enough not to.
Casting the enthusiasm and hopefulness of people for a better future because of their choice of leaders as some sort of jejeune obsession is, on reflection, pretty uncharitable and even a touch anti-social. I am sure there are people who are madly obsessed with him in the same way rockstars sometimes induce young people to get, but on the whole it is distinctly possible that the hypothesis is a shitty one, fueled not by reason but by some internal bitterness. Sorry if this seems unduly harsh. I think the proposition is...what's the word...thinly disguised underhandedness.