I wouldn't be surprised if some liberal activists perpetuated this stunt.
Because this is the most logical pathway of thought.
You know, as opposed to just admitting that a sizable percentage of your electorate is nothing but a bunch of hardcore racists. I don't see why you can't accept the logic that in an audience of thousands of polarized, partisan Republicans, that at least a couple of them are going to be racist enough to do something as bigoted as this. After all,
30%+ of Republicans still believe Obama is a Muslim despite having no evidence to suggest such a thing. Among this Republican audience of knuckle-draggers,
56% of Tea Party identifiers, 50% of evangelicals and 41% of all Republicans believe Obama was born in another country. When you add in the "doubt" factor, the number of Republicans who engage in this bat-shat behavior grows to 65%.
This will certainly be a good fundraiser for Democrats, who seem to be promoting a race war.
Oh, you mean how the Democrats are counterattacking Republicans for executing a war on race? Don't get your panties in a wad when your party dog whistles for four years only to have the Democrats come up behind you with a foghorn.