There are people on the other end of the email who are doing this for some rational reason, not specifically to piss you off. Generally, acting nicely to people you don't know well will get you a lot more than being hostile.

    Hi Quora team,
    
    I'm not very happy with the recent changes to privacy settings on Quora and I'd
    like to delete my account. My email address is ...
    
    I've heard from others that, in lieu of their account actually being deleted, their
    followers and username were just reset. Could you ensure all the content I've
    created is fully *deleted and gone from your database*? I'd do it myself but all
    you can do is hide it.
    
    Thanks again for your help. It's unfortunate that it's come to this, but I'm just
    not at all comfortable with your new policies and so I want to make sure my
    persona on the site is truly and completely gone.
    
    Best

(Also, "deleted permanently without a trace." is absolutely impossible in the current age. Even if Quora did manually remove everything from their databases, cache servers, logs, etc, they'd still have to figure out some way to remove it from search engine caches, API clients, and anything else which is, in all actuality, totally beyond their control. Whether regular users realize this or not, as a member of a community called "Hacker News", I fully expect everyone here recognizes the state of things, and the irreversibly of creating something.)

Quora is acting badly. You don't start exposing "views" like this without at the very least warning users in advance, and more reasonably, defaulting to "off" for existing accounts.

You also don't have a "Delete" button that simply hides things. That really is unconscionable. Delete means delete.

I've been on the receiving end of thousands of user emails and that email is not even a 1 on the hostility meter. Personally I tend to appreciate very simple and direct email. The hardest users to help are the ones that aren't clear about what they want.

Okay, "deleting without a trace" probably should be "delete as much data as you possibly can". Remove from backups, archives, caches, do not simply "hide" my data, but delete it permanently. Every service should develop a process for doing this. I've developed this kind of functionality many times, and yes it's a pain, but no it's not particularly hard. Quora is clearly not responsible for Google or any other third-party generally.