The purpose of many memes is to make your pov seem more relatable. Even OP's meme is an example of this. Then you have the comment section, which serves to reinforce relatability of the meme, and then the upvotes which are a digital "amem" or "yeah".
So in a way, memes on redditlike sites are more or less a propaganda machine with a feedback system built in. Want to push a political pov with little effort, and an automatic way of gauging popularity while showing users "See! I'm not the only one!" Post a meme with a political message tied to it.
Also, a lot of people seem to call anything they don't agree with "political" as well, so sometimes a harmless meme about being gay gets grouped with a meme about eating the rich.
The point is as long as people have different point of view, memes pages are always going to seem political. Combine that with the fact that lemmy.ml tends to be more leftist than reddit politically, it might come to a shock to a lot of libertarian mind refugees who are used to their humor being accepted, or leftists who are shocked by the kind of content they're seeing on their front page.
There are several different memes spaces on the fediverse. The only real solution I can give is to block the ones that don't meet your standards, and build up the ones that do. Considering the different natures of each instance, I'm surprised each one doesn't have its own active meme page.