Seems like it only takes one or two accounts to spam some related memes to get to the front page. A while back it was Taylor swift's carbon emissions and before that it was the US and oil.
But who's spamming? Looking through this community, there was one guy who posted a screenshot of a tweet about "jairs" and shitposts just escalated from there. Seems like lots of different people have contributed one, maybe two memes. Point is these things do happen organically sometimes, you don't need to assume it's some conspiracy