YouveCatToBeKittenMe

To add to what other people said: As a casual user who didn’t go deliberately looking for bots, I mostly caught them when they posted a comment that was a complete non sequitur to the comment they replied to, like they were posted in the wrong thread. Which, well, is because they were–they were copied from elsewhere in the comment section and randomly posted as a reply to a more prominent thread. Ctrl+F came in very handy there. (They do sometimes reword things, but generally only a couple of words, so searching for bits and pieces of their comment still usually turns up results.)

Also, the bot comments I caught were usually just a line or two, not entire paragraphs, even if they were copied from a longer comment.

I remember being good at google-fu, and then thinking my google-fu was failing me.

No, it was the Google that failed me.