Moran Gary, count ALL of the heads in that cartoon. It's probably roughly the number of illegal aliens who have ever been proven to have illegally voted in an election.
It's REASONABLE for very uninformed people to think that the Democrats welcome illegal immigrants so that they'll vote for Democrats. Except that I don't believe that there's much, if any, evidence that it happens anything more than rarely, and in meaningless numbers.
Look at it this way, if you shed JUST the stupidity of being receptive to a cartoon like above, you get to:
a) Tell yourself that you're THAT much less a moran. And,
b) Laugh at (at least some) libs for hoping for something that doesn't happen.
Not bad.