So what is the comment frequency of these bots? There must be some signal in the activity even if the comments themselves pass the turing test.

Even if there was, I doubt Reddit cares enough to go after them when it’s boosting their valuation

If you find one account you can find a few dozen spam accounts by building a graph of what posts they reply to

Most of them have private profiles these days

Does it matter? With enough you can just have them upvote each other.