I upvote memes based solely on whether or not they're funny, clever, or pithy. Whether it's political or not, and whether it has a left/right bias shouldn't enter into it. I rarely downvote anything unless it's especially bad.
Some years ago, I was a right-wing political ideologue on a number of message boards and I determined that I was NOT going to let myself get political on IMGFLIP. It hasn't been easy, and I've fallen off the wagon a couple of times.
The thing that makes this place great, is that "funny" rules the day (or at least it's *supposed* to). Sure, there's plenty of 'stupid' out there, too (Hillary is an ugly witch - HERP, Trump is mean and has orange hair - DERP). But the upvote/downvote system should be based on whether something is funny or clever (preferably both), and not whether or not you agree with the sentiment.
Unfortunately the people with the glass feelings (on both sides) are taking over this place, and if anyone has any ideas about how to put a stop to their shenanigans, I'll gladly help. I want Imgflip to stay a place where people can laugh at themselves as well as at everyone else.