It is not hard to identify each abuser, my point is that in a large pool you will have lots of small abusers to go thru and vet. When someone is using dedicated IP that's what it is. Its dedicated so you immediately know whether the actors acts in bed faith or not (perhaps sent a few more-than-usually-spam-looking messages).

I don't know whats going on with Sparkpost honestly. I actually uncovered a large international scam artist (CNN did an investigative reporting on similar one milking population to the tune of $400MM/annul) with over 30 dedicated IPs running thru Sparkpost network, but frankly they don't care. I reported that multiple times and also tried to talk to them about it over twitter but they quickly banned me. I think their rules in terms of anti-spam/anti-scam are more guidelines than rules they abide by. I would imagine someone with such vast setup brings tens of thousands of dollars in revenue, so that makes sense why they would turn a blind eye. Its sad actually, the CNN reporting was about broken families and suicides that were to some degree a result of emails' content that perpetrators sent (like romance-type scams send to seniors in hopes to get them send money oversees).

I guess if Rich Harris sleeps well at night knowing his company abides in scam artists pushing senior citizens into taking their own lives, then the business continues as usual. But its sad IMHO nonetheless...