It shows bigotry and prejudice of the worst kind. That is why you cannot have a rational argument with a liberal. They have already made up their minds as they lump all of those catagories of groups together and imply that we all are racists and potential murders just waiting for a chance to shoot some pregnant Mexican in the head.
In reality the cartoonist is on the same side as the true racists like neonazis, he just isn't smart enough to recognize it. The neo nazis and their "kind" hate the minutemen.