Cleaning accounts from your password manager and cleaning your accounts from the internet are two very different things. The article and my comment were about t

Cleaning accounts from your password manager and cleaning your accounts from the internet are two very different things. The article and my comment were about the former. I agree with you though, that a well-known url for delete would be good. However, there's likely to be a high correlation between sites that get breached and sites that don't follow best practices, including implementing optional URLs like that. In general, it's also easy to see why a lot of (non technical) site/product owners wouldn't want to implement that: "why do I care about making things easier for people that want to terminate doing business with me?" Until a majority of users are using a browser/plugin that warns about this ("non trustworthy site: this site does not implement well-known password change or delete account interfaces") I suspect there won't be much adoption, unfortunately. This proved to work well to get SSL widely deployed, so the question is if there can be enough momentum to do it again for these functions.