This has also perplexed me (advertising-to-bot-relationship), but I'm guessing the cost of combating these bots is going up (as complexity goes up and token cost goes down - whether subsidized or not).

I hate the idea that the future is only gated invite-only groups though. At the very least, some tag of "BOT" and then the ability to hide all bot content (unless it's highly upvoted by humans) would be great.

Any attempt to seriously combat bots would most likely impact real user engagement numbers so it is indeed a tricky business problem to solve.

But I can't see the Reddit comment change as anything other than a cynical "astroturfing as a service" to advertisers. Doesn't seem to be working out for them though given their stock performance this year.