As much as I feel that Reddit was pretty underhanded, I doubt that they're using AI to fake content to keep people on the site 'cause (a) people would catch on pretty fast by looking at the history of the account and (b) running LLMs probably cost more than the earned advertising revenue.
What's more likely is that people/bots have always been reposting for karma a while
I like coffee and I like vectors. I made it in high school and thought I'd be one of those names I regret, but even now I still like it.