My bad, I tought you were talking in general. I'm not familiar with DDoSecrets so I cannot say much about their case specifically.
What I can say though is that generally the threat model for attackers slightly more sophisticated than script kiddies suggests that the preparations involve a non negligible amount of time from highly specialized engineers and that somehow, someone has to pay for it.
Highly specialized engineers can be motivated by non monentary ideology just like everyone else.
Besides i think there are plenty of bored teens/uni students who fit between script kiddie and mafia/state actor on the sophistication scale - its a pretty wide step from script kiddie to professional malware writer.
What I can say though is that generally the threat model for attackers slightly more sophisticated than script kiddies suggests that the preparations involve a non negligible amount of time from highly specialized engineers and that somehow, someone has to pay for it.