Technology

If I got this right, what most people call "slop" is mass-produced and low quality. Following that definition you could have human-made slop, but it's less like a low quality meme and more like corporate "art". Some however seem to be using it exclusively for AI generated content, so for those "human-made slop" would be an oxymoron.

Human reviewing is not directly related to that. Only as far as a human to be expected to remove really junky output, and only let decent stuff in.

Vibe coding actually implies the opposite: you don't check the output. You tell the bot what you want, it outputs some code, you test that code without checking it, then you ask the bot for further modifications. IMO it's really bad, worse than what a non-programmer (like me) outputs.

so then is responsibly-trained output of AI, like using DeepSeek on a personal machine where someone pays for their own electricity, okay?

That'll depend on the person. In my opinion, AI usage is mostly okay if:

• you don't do it willy-nilly. Even if you pay for the energy, it still contributes with global warming and resources consumption. Plus supply x demand effects.
• you're manually reviewing the output, or its accuracy isn't a concern. For example: it's prolly OK to ask it to give you a summary of a text you wouldn't otherwise, but if you're doing using it to decide if someone is[n't] allowed in a community then it's probably not OK.
• you're taking responsibility for the output. No "I didn't do it, the AI did it!".
• the model was responsibly trained and weighted, in a way that takes artist/author consent into account and there's at least some effort into avoiding harmful output.

conversely, what about stealing memes on the internet and sharing those without attribution as to the source

Key differences: a meme is typically made to be shared, without too many expectations of recognition, people sharing it will likely do it for free, and memes in general take relatively low effort to generate. While the content typically fed into those models is often important for the author/artist, takes a lot more effort to generate, and the people feeding those models typically expect to be paid for them.

Even then note a lot of people hate memes for a reason rather similar to AI output, "it takes space of more interesting stuff". That's related to your point #6, labelling makes it a non-issue for people who'd rather avoid consuming AI output as content.

piracy

It's less about intent and more about effect. A pirated copy typically benefits the pirate by a lot, while it only harms the author by a wee bit.

Note I don't consider piracy as "theft" or "stealing", but something else. It's illegal, but not always immoral.