Can you also describe exactly what the connection between CyberBunker and the attack is. Is there any indication that the hosting company is actually involved? It seems dubious but of course there are defunct hosting companies that have done such things (Russian Business Network comes to mind). However, this host does not seem shady in comparison to RBN.

It has an actual location. The name of the owner is known. It has evidentially been involved in legal disputes so it is on record with the government.

Much more likely is someone using the hosting system for something nefarious is retaliating against spamhaus. I don't think the hosting company should go down for that.