Frankly, slop isn't an exclusively AI phenomenon, it's just that it becomes a crazy large concern because the slop creators can crank out with souh volume with GenAI.
It absolutely still has a meaning, it's time wasting hollow content devoid of value.
When AI generates non-slop, well, we can't really tell to call it out. When a human inflicts slop on me without AI, I'm still not happy, but there's only so much they can do on their own...