The basic problem seems to me MailChimp's assumption that people only upload address lists from users they have consent from, when in reality everyone just uploads their LinkedIn address books and hopes not too many will press the "report" button. I am seriously fed up with Mailchimp not taking any actual action against these users after I already told them that I don't consent to receiving any messages about any topic from anybody via their platform. MailChimp should add a feature IMO where if somebody uploads an email address of people opting out that this person will be blacklisted from further using MailChimp.