For better or for worse, when threads on such topics run to high page counts, it's generally because one or more posters disagree with the premise, and the resulting debate is what draws things out--e.g. the Allen thread (where the very first reply was to disagree), the Virginia slavery resolution thread, the Grey's Anatomy thread, Mel Gibson etc. Speaking for myself, and since the Allen thread seems to be the point of comparison here, I never personally called Allen a "bigot" and only posted in that thread to get people who disagreed with its premise to explain what "macaca" meant, if not a racial slur (and I didn't feel I ever got a convincing response). I suppose if someone regularly posts simply to express unadorned judgments like "Disgusting" or "What a bigot" in threads featuring alleged Republican racists, but not Democratic ones, then yes that would be hypocrisy. But not everyone makes posts of that type. Biden wouldn't get my vote and I agree his comments were repulsive, however, for FYM purposes I really don't have anything substantive to say about them, unless and until there's something to be analyzed and debated in either his words or someone's reactions to them.
However, if MrsS is willing, I'd be happy to separate out the posts about Biden's Obama comments into a new thread and see if anyone wishes to deny that his comments were racist (or critique that labeling of them, etc.). Other than that, I agree with MrsS' response--by all means, go ahead and start threads on Biden or whatever other Dems you think are bigots if you feel that gets chronically short shrift. I think that would get the message across more effectively than only bringing it up as a tangent in threads about 'incidents' involving Republicans. Perhaps it boils down to a question of what you think threads like that are 'for'--I tend to see FYM as "Sit down and discuss" not "Stand up and be counted" so personally, I wouldn't conclude much of anything if I posted, without argument, an article about someone making a racist/sexist/anti-Semitic/etc. comment and hardly anyone replied. IMHO, it's a little silly to treat an online forum as some foolproof barometer of what people "really" stand for, for good or for bad.