> antithetical to the principles of the open internet.
No. These blocklists are employed by the actor receiving the email. They have a perfect right, even on "the open internet", to decide that they want to limit who can send them messages.
There are tons of checks on the people who provide those blacklists, in the form of their users complaining about lack of mail delivery and ultimately not using their list anymore. We vote with our wallets, and as a group we have decided that these blocklists are useful.
No. These blocklists are employed by the actor receiving the email. They have a perfect right, even on "the open internet", to decide that they want to limit who can send them messages.
There are tons of checks on the people who provide those blacklists, in the form of their users complaining about lack of mail delivery and ultimately not using their list anymore. We vote with our wallets, and as a group we have decided that these blocklists are useful.
> and for what?
To make email usable. Full stop.