I'm not an instance admin, so I don't speak for them.

From my perspective, I don't want to see that kind of meme in my feed, but I also don't think that alone is enough to defederate. That meme along side all of the rest, though, shows that this particular admin enjoys posting troll content, rage bait, and hateful material.

Now, go take a look at the rest of the content on the instance. It isn't all bad but there is a high ratio of hateful content there relative to other instances.

So, while that one particular post may not have been the worst thing in the world, it could be seen as falling under "harassment" in the Citizen Code of Conduct and shows the general mindset of the instance admins. When taken together with the admin's other posts and the prevalence of hateful material on their instance, it indicates that the instance is unlikely to be a welcoming place and will likely continue to violate the Lemmy Code of Conduct and the Citizen Code of Conduct.

I'm happy that lemmy.world has defederated from exploding heads and might have moved to a different instance if they hadn't.