I think this may have been a case of the “dirtbag left” types using slang that originated on 4chan, I did a search with date restrictions on the 4plebs archive site and found posts using it for mindless entertainment going back to 2012 at least
Great comment, I agree that this stuff all seems connected. My speculation is that something similar may happen in the future if they try to implement continuous learning with synaptic weight changes, not guided by either labeled data or constant RLHF with a human teacher–without frozen weights or human guidance in weight changes, such continuous learning models might have a strong propensity to develop feedback loops (sort of like self-wireheading) that look like strange “obsessions” and the model becoming increasingly solipsistic and hard to make sense of, a la spiral-talk. Animal brains have developmental pathways constrained by a huge number of innate sensorimotor biases, which in humans include ones related to the development of sociality and caring what others of our own kind think while building more sophisticated models of their minds, but those biases have been fine-tuned by millions of years of evolution to work with one another and with typical environmental conditions to guide how the brain changes over time (I think this would be a case of what evolutionary biologists call “canalization”: https://en.wikipedia.org/wiki/Canalisation_(genetics) ). Artificial neural nets wouldn’t have that, and this could end up being a basic obstacle to developing more humanlike long-term learning abilities in any kind of near-term future.
Searching google books for “reading slop”, this usage seems to be very sporadic (only 11 hits for 20th century publications), I’d think it was more just a case of independently coming up with the same shorthand rather than causal influence, whereas slop seems to have been used this way frequently enough on 4chan that it seems much more likely there was an actual chain of influence to later use on twitter and elsewhere, especially since a lot of other 4chan slang has later broken out in that way.