Cain has already clarified himself on this issue. Judging by his high polls numbers, to date, this hasn't been a problem.
Obama supporters are just looking for something, anything with which to hammer Cain, because they are frightened. If a GOP candidate can get the conservative base fired up, coupled with the independents (which are leaving Obama by the truckload), he'll cruise to victory, clobbering Obama and the Dems by margins even worse than that of 2010.