Whites in Illinois voted for Romney by a six point margin in 2012, but because non whites are 30% of the electorate there and gave Obama a 70 point margin the state went blue. So race is a factor there, if Illinois were as monochrome as new England then Romney would have won instead of losing by 16 points.
I never said it wasn’t a factor; Cook County is 1/4 black and 1/4 Hispanic, after all. And, yes, non-whites voted strongly for Obama (but don’t discount the fact that Obama is from Chicago, as well).
But, it’s not the only factor, by a long shot, as I described. For one thing, if race were the primary factor, then Chicago wouldn’t be at 26 years, and counting, since it’s had a minority mayor.
It’s probably not as strong as it was when Richard M. Daley was mayor (and certainly not as strong as it was in earlier decades), now that all of the financial chickens are coming home to roost in Cook County (and in Illinois, in general), but it’s surely still there. Clout is still very much a thing here.