There's worse. An unsubscribe link that asks you to submit your email. Few things anger me more, because they went through the trouble of pretending to comply, and a decision was made to make my day more difficult.
You can probably guess how effective that is. In practice, unless you can get the FTC or a state attorney general to sue an actual company for you, nothing will ever come of it.
Lot of people, especially of the older generation, forward all sorts of emails to their friends and family every day. If one person who received a forwarded email doesn't like it and clicks the unsubscribe link, the original recipient (who clearly likes the email enough to forward it around) gets unsubscribed. That's a bug. If you don't like the unfunny newsletter your uncle keeps forwarding you, that's a problem between you and your uncle, not between your uncle and his newsletter!
The email submission form exists to ensure that the person unsubscribing is the person who is actually on the mailing list. It will not prevent an annoyed nephew from deliberately unsubscribing the original recipient, but it will prevent most cases of mistake by third parties.
Similarly, many unsubscribe links require two clicks instead of one, because some email services used to automatically check out every link they found in the body of an email. A one-click link would unsubscribe everyone before they even saw the email. Nowadays we have better protocols and better email scanners, but old industry habits die hard.
That comment explains that there's a scenario where people can be accidentally unsubscribed in the presence of mail forwarding, and the requirement to enter an email address can patch over this.
Thankfully I don't have people forwarding emails to me outside of work...
The page can prompt the email address, and have a simple unsubscribe button. Not perfect, but okay.
Even better, one-click unsubscribe features (e.g. Gmail's App) are presumably set up to work for the current recipient (not the original sender) so the problem is resolved for anyone using an email client with inbuilt unsubscribe.
The forwarding problem is only for html link unsubscribe. Personally I hate trying to play find-the-ubsubscribe-link, so I use the email client feature where possible (which also helps Gmail rate/flag spam).
Mostly I haven't had problems with repeat spammers, except a republican politician (I'm not in the USA so doubly annoying).
I understand the parent's sentiment because we all want to unsubscribe from unwanted emails. But technical standards can't distinguish unwanted emails from business-critical emails. You could legitimately cause someone damages by silently unsubscribing them from an important news feed. (Imagine that you silently unsubscribed an open-source maintainer from all github notifications!) Even worse, this kind of vulnerability disproportionately affects senders who try to follow the rules and make it easier for people to unsubscribe. Spammers don't care and keep spammin'.
Ideally, an email would have both a one-click List-Unsubscribe header and an HTML unsubscribe link in the body. The latter need not be one-click, and in fact, if it's anything remotely important, should not be.
Do open-source maintainers forward around their unsubscribe links in practice?
The other problem with email scanners clicking links automatically can be solved without prompting for the email address. One simple solution is: if the link is clicked within a minute or so after sending the email there's a chance the clicker is an automated system. Instead of unsubscribing right away, serve a HTTP POST form with a single "Confirm Unsubscribe" button. Normal users will rarely see the form, automated systems will hesitate to fire off HTTP POST requests.
It absolutely should be one-click.
I’m a republican (also not in the US sense — I want to get rid of the tie to the monarchy) but I also find that republican politicians seem to be really annoying!
Some people have come up with a trick to hide the unsubscribe link with CSS when it is inside a <blockquote> tag, as in a forwarded email. It doesn't work reliably, though. HTML email is still stuck in the 90s, it's impossible to do anything fancy inside of it. Much easier to send the user to a real web page for an actual transaction.
Email providers autoclicking on links, is the recipient's problem. This is the same flow used for account verification links and yet you do not see them adding an additional step to it.
And then we have the large number of users complaining about this, and yet they feel they simply know better and reserve the right to impose themselves on us?
This decision is purely self serving, let's not pretend otherwise.