Whatever one might think about confirming opt-ins I think we can all agree that requiring someone to jump through hoops and confirm an unsubscription request will just annoy that person.
Today I attempt to opt-out from a discussion list. It’s one I *thought* I had opted out of previously, but I could find no record of the request anywhere. OK. So I imagined unsubscribing, I’ll just unsub again and keep better records.
After digging through the headers, I find the unsub link and dutifully mail off my unsubscribe request. I then receive an email that requires I click on a link to confirm my unsub request. This causes me to grumble a bit. I have heard all the arguments about forged unsub requests and the various reasons this is good practice. I believe none of them. Requiring people to confirm an unsubscription request is bad practice.
In this case, the mailing list is a discussion list so there is no CAN SPAM violation. However, I know that some commercial mailing lists have also implemented confirm your opt-out request. For commercial mailing lists, this is a CAN SPAM violation. It’s also just plain rude. If someone says, “Stop!” then you should stop, no questions asked

CAN SPAM • unsubscribe • unsubscribes