The coconut is an underrated comedic fruit. Bananas get a lot of the attention when it comes to fruity humor, but this isn't a one plant show. Coconuts are also plenty amusing, in their own way. Their shells make a funny sound, and they're very good for bonking people on the head with. Even better, the trees they grow on can do this naturally.
On top of this, we can't just celebrate coconuts for their entertainment purposes. They're also a versatile and nutritious food, as well as perhaps the only fruit that can be eaten and drunk in its natural state. This alone is a good enough reason to look at some memes about them, but it helps that they're also pretty amusing as well. Memes about food are a great innovation in funny internet pictures. When they decide to get specific, that makes the whole experience of them even better.