The entire point of this move is part of their "dealing with antispam bullshit" service. What Mailchimp offers is not mail delivery. Anyone could provide that cheaply at near-unlimited scale. What they offer is the opportunity to piggyback on their good reputation as senders. Maintaining that reputation is necessary for the operation of the business.

> just deal with the fact that many of your messages will never arrive

This isn't quite right. It's more that your messages will be rejected at the destination.

I go through my mail once every couple of days, and I've learned to recognize "refinance with us" or "sell your house" mail by sight and throw it away unopened. Now, if I see an envelope that says (for instance) "Internal Revenue Service", I'm going to open it up. That's because of the good reputation (in a certain sense) of the sender.

The mortgage people could slap "IRS" on their mail and have a lot more people open it and read it. They would also have a number of stern, suited people come by to discuss federal law with them. But that wouldn't be censorship. It's not censorship to withhold your endorsement of someone else's communications.

Just because it's not as easy as using `<?php mail(); ?>` doesn't mean Mailchimp has some kind of monopoly that makes their acceptable use policy the same thing as censorship.

So, in a way, Mailchimp is actually in the business of getting around censorship in the form of spam filters?

That's where people should be directing their ire, those anti-free speech spam filters that prevent an honest businessperson from filling up their inbox with a multitude of "great offers".

Oppression in the first degree, that's what I call it...