No, it's valid for me, and I just verified. In spam filter for past month: 0 mailchimp. In valid emails: 6 emails from a service that I signed up for via mailchimp.

Checking my received emails for mailchimp I see a whole bunch of legitimate emails, including for flightschedulepro which uses it. I also see replies to my abuse reports to mailchimp saying the problems have been addressed.

Do you report any of these spams to mailchimp?