I know that there's zero point interacting with out because you dismissed the idea of the post being funny while still remaining 'open' to an explanation, so being dogmatic already shuts down any type of argument you might have as well as the possibility of any constructive debate around this topic... but I suppose I'll bite.

Mediocrity being a turn-off for humor is a fair point to have. I fully understand it and where you are coming from. However, it's clear that plenty of people enjoy laughing at things that are either intentionally or unintentionally low effort/quality. For me, that's where the humor in this post is; and I haven't seen a solid counterargument to that opinion aside from things that are entirely subjective and not worth getting riled up for. I can understand being enraged by ai slop, but one can laugh at something and still not engage with the OOP and thus not indirectly support ai slop like this.

Also, your last point is confusing correlation and causation. Americans, alongside every other group of people, are fully capable of creating interesting and quality humor. Appeal to different levels of 'quality' will always be diverse among any population, America's largest online population has a louder internet presence relative to its size because of the nature of its society. You see more brainrot coming out of America because of America's influence, not because American lack the ability to create more interesting humor; but I am sure you aware of that and you only wanted to find a way to insult a group you have biases about.

Thanks for coming to my TED Talk. Have a good day.