I’m hoping that the bot saw its posts were not posted any more and so has stopped.
I was unsure at first if it was actually a bot or a person posting them, but looking at the traffic you can see a huge spike in activity around when the posts are made, which would suggest it’s a bot.
Interesting that it’s able to pass reCAPTCHA, either Google’s bot checker doesn’t work, or more likely there probably is a human element where someone has to manually check each one. That sounds quite depressing so best not think about it.
Of course it could be signing up using stolen gmail accounts that are pre-approved by Google.