The only legitimate reason to conceal it is you consider it problematic.

I get what you mean, and agree that the AI slop is bad and should be declared... But I'd argue that "considering it problematic isn't the only reason to conceal it.

There obvious financial motives. If you don't think it's problematic, but think it'll hurt sales then that is a "legitimate" reason. It's a morally shitty reason, but it makes sense.