I've seen a lot of people doing this. Maybe we should have a public database of what company sold emails to who that everyone who did this can contribute to, with some kind of proof required.
Obligatory mention: https://haveibeenpwned.com
It would be important to stress it out on the page that it may be due to security negligence/failure rather that just data sale.
I’m working on something I call “datapoint tax”
Make this hoarding of data a (tax) liability. A policy like this will solve most problems.