"Maybe it's on Slack (or Teams), a text message, or an email. Maybe you were tagged in Notion or an Office doc."

I'm 55 years old. "slop" is way older than your examples. Try a dictionary, eg: https://dictionary.cambridge.org/dictionary/english/slop

LLMs are tools. For me (wot had a C64 as one of my first computers) they are seriously close to magic but I understand what a "next token guesser" means.