I'm very surprised to see you are being downvoted, I was convinced everybody is doing that. Spam is spam, period. Asking me go click on a link that leads somewhere is just a waste of my time - and there are still a few culprits out there who instead of unsubscribing me straight away demand that I log in to "manage my notification preferences"!
I'm not even their customer (and never will be), so not really sure what kind of app functionality they'd be claiming. :/
But the concept of your comment "they're just doing what they want because they reckon they can get away with it" is pretty common among large tech companies.
After feeling gaslighted by some spam emails that I was very sure I had unsubscribed from, I started keeping a spreadsheet to track my requests with date, and what link I followed to get removed. Almost 25% of my requests have never been honoured, it's disgusting.
But when you have dozens of databases, each owned by a different company, and they feed off each other perhaps once a day, then you can end up with a long time before all your data is deleted.
And that’s their problem, not mine. If they structure their email campaigns such that it takes a long time to update every database, that’s a design choice on their side. When that design choice means they effectively ignore my unsubscribe, well, I don’t see why that should receive any sympathy.
I own my own email domain, and I use a different email address per service. I have done so for 13 years.
On legitimate emails, unsubscribe works correctly almost every time.
True spam seems to originate from a handful of compromised services like LinkedIn, parkmobile, etc. I don’t hit unsubscribe on those, but I don’t see how it would make things any worse.
Are people still using that for tracking? I thought it was made pretty pointless by the large cloud providers simply prefetching and proxying it through their servers, and independent mail clients only loading them on-demand.
Nearly everyone has their client configured to do that, because it is the default setting. Gmail makes that very easy to change, but many other clients have it buried in the menu