It is an admin for each AS. Each AS that has a direct connection to the abusing AS would need to put a stop to it, otherwise risk being seen as complicit themse

It is an admin for each AS. Each AS that has a direct connection to the abusing AS would need to put a stop to it, otherwise risk being seen as complicit themselves. Hops further down could blacklist an AS as well. Large ISP's may have multiple people that can affect these policies.