I'm reasonably confident there is no argument that I would buy.

I hate AI slop more than average, but this is not slop being injected into human places. This is a dedicated dumping ground for slop, paid for by the owner/instigator of said slop. I don't have to go there, and it's not trying to fool anyone and no one will be fooled by it.

AI slop on a forum or social media or on facebook convincing boomers that a black person slapped a cop or whatever racist garbage they're being fed today? Fetch the guillotine.

AI slop as part of a dumb art project on somebody's personal website that isn't trying to manipulate or mislead? Have at it. Go nuts. It's your press, print as many pages of slop as you like.

So, I have exhaustively covered the possible arguments I can come up with for why this could be "actively harmful for the web", and rejected them outright.