Thanks so much for the insightful responses. You're right regarding the millions of ways to attack and that it's a fact of life. As long as there are other tribes there will be rocks to throw.
I didn't realize how much of Usenet was full of bots. I can imagine spam and trolls but it's interesting to think about the early days of bots. I take it for granted that the problem has been around for longer than companies centered around mitigation. It's heartening to know that you all handled it so well then and that the bigger instances built on ActivityPub are managing too.
On your point of mitigating these issues as they scale and grow, I completely agree. Previously in my career I worked on analyzing and mitigating malware. Bots are similar. It's a cat and mouse game. Regardless of how well we manage to detect and stop the tools bad actors use they will always find new ways to circumvent those methods. It's good job security.
You're doing great.