Caveat: I don’t speak German.

I guessed that this was a wordplay on more/less in German so I checked the original German meme in the link which shows the words meer on the left and weniger on the right. According to my translate app, the word “mehr” means more and the word “meer” means sea. (Weniger means less) I’m guessing meer/mehr are pronounced similarly and that’s the joke but idk.

Meer (sea) sounds like mehr (more)

Well there's sea in the first pic. And then there's less sea in the second.

(I don't get it either)