Waste of breath. With some people it's a religion. With others, it would mean admitting that (at the least) they made a terrible mistake or (at the most) all of their previously held beliefs are equally questionable.
Doesn't matter HOW bad things are, if he runs, Obama will get a minimum of 40% of the vote in 2012. Period. End of statement. Doesn't matter if they're voting for BO because he's black, or they vote straight ticket Dem, or because their Daddy is a Republican and "They'll Show Him!!!", or what. The trick for us is going to be finding a candidate to support who will get 1% more.
IMHO, the secret is to let people figure things out for themselves - like my friends were. Maybe a gentle nudge "Geez, my 401k is really tanking, what's yours doing?"...but no more than that. Pointing out how STUPID they were not to see Obama for the con man he is, and to castigate them for voting Dem, just drives their defenses up and makes for an argument. It might be satisfying, but it accomplishes little.
I agree with you.