I did read the weisberg piece, and I agreed with it. If Obama was white, he would be up by 20 points right now, if not 30. McCain is the standard bearer for the party of catastrophes - Iraq, Katrina, climate change, energy strategy, and now the biggest of all, the imploding economy. And to top it off, he picked someone with so little knowledge and understanding of what is going on outside her little world, and how it works, for VP nominee. There is no reason for the race to be as close as it is.
McCain did not win the Republican nomination, all of the other candidates lost because of indefensible positions on two of the biggest issues (Iraq and the economy) and personality deficiencies, he was the one left standing. A better race for president would have pitted Obama against the only candidate with true republican ideals, Hilary Clinton, but Obama beat her in the semi-finals. McCain desperately wants to turn this into a race on character, but if there was enough time to distract voters' attention away from the economy, the truth about his character flaws would lead him to defeat anyway.
Weisberg didn't say the only reason that people are supporting McCain is because Obama is black, but that there are enough voters who don't feel comfortable about him being president to make a difference. You shouldn't be insulted, lots of people have non-race reasons for supporting McCain (not that any of them make sense).