It’s an inevitable outcome of its structure. With memes, it’s usually just the low-information image, which is typically visible from the post listing. There’s no article to read, no video to watch (or just a very short one), no question to think about, and you can upvote it straight from the post listing, so there’s not even a link to click. In other words, memes have a very low barrier-to-upvote compared to other types of posts, and as a result, are more likely to get upvotes and end up on the front page.

For serious conversation what you really want is a forum or only join communities on Lemmy where memes are frowned upon.