That faq section on comeso is absolutely ridiculously condescending. This does confirm that most of the big publishing companies both japanese and korean use a third party for dmca. Probably explains why it is so heavy-handed as well as they probably would have an even less nuanced view considering their business model.For those who want to know the extent, the claimers, etc, they also reported it all to Google (so the URLs are removed), so Lumen have it all.
https://lumendatabase.org/notices/search?sort_by=date_received+desc&term=mangadex
One of the biggest players seem to be this one (https://comeso.org/) on behalf of a lot of people