No one is whining about being put on an email list at their own request. Which you obviously know. People were making the point that newsletters aren’t magically immune to data tracking.
You can bet your ass the MailChimp is sharing a fuckton of data with advertising partners in order to maximize sales to you. It’s not supposed to be controversial. I first just assumed this was something you hadn’t thought about. Sadly you seem hostile to information you hadn’t considered.