I'm not an expert, but most forums I've been on didn't have a "remove me from this site" button - due to how the forum software was written. Administrators can remove users on some software platforms, but I wouldn't assume it can be done easily on every one.
I dunno who put a stick up your rear, but it sounds like you don't want to be here. If you don't want to participate in OCDO any longer, just make sure you aren't set to receive emails on subscribed threads, log out, and don't log back in. Easy-peasy.