I recognize a lot of the users who do this. They're a bunch of free speech crybabies. So they get the perfunctory downvote. But I can't spot them all. I hate it when I click on a meme with no comments and given them a view. Hopefully my downvote helps to balance that out a bit.
There is a difference between users that comment and those that just do drive by insults, with no comment on the subject of the meme. I don't waste my time responding to trolls.