I don't think Niu Lai is slop. They put a lot of effort and passion into that, even if they didn't have the skills, or know how to learn about how things are "meant" to be done. Slop is when you didn't even try, didn't even care about the output. There's plenty of humans who create slop, human spam.
Niu Lai is maybe more like Outsider music. The movie equivalent of "My Pal Foot Foot" by The Shaggs. They tried their best without knowing what they were doing, and ended up influencing artists like Frank Zappa & Brian Eno: