The claims probably have little to do with DMCA violations themselves, but it has become an easy way to get content removed quickly from sites without very much

The claims probably have little to do with DMCA violations themselves, but it has become an easy way to get content removed quickly from sites without very much review from the host service. The claims are probably from the malware perpetrators as a way to censor discussion and keep the gravy train rolling. It's possible also that the embarrassed commerce sites would file a DMCA claim to keep the public in the dark about how insecure their sites are/were.