OK, a twenty year association is ample time to run the whole gamut of human experience, at least in social/religious/political contexts in a setting like a church, wouldn't you say? If in that time he also witnessed principles propounded by the very same pastor that represented the very highest achievements of human dignity, then is his also tainted by association to the good?
What kind of balance obtains here? Weighed in the scales is Wright only a man who must be repudiated, or is there another side to his character? Are there many sides to his character? And is Barack Obama guilty by his association with only the most negative one? I think the white men you allude to are quite capable of comprehending the nuances here. It's not that complicated to see that people are complicated.
Supposing you'd also witnessed glorious things in Wright's church, profound acts of grace and generosity and goodness, are you going to pack it in because of the things you don't like? I know we're stuck with our fathers, but you brought up yours, and Obama has called Wright his spiritual mentor, kinda like his spiritual father.
All told, though, you're probably right, as are Schadenfreude and TNT above. Obama is boxed in now and a great speech about the Ashleys and old black men of the US won't cut it. Personally, I think it's the height of indecency to dump him over this, but I'm not voting so my opinion is irrelevant anyway.