Google, et. al still sees and indexes member pages for groups a member has left, as the page exists with "Sorry, this account no longer exists." but not with a proper 404 type HTTP response. So the page is perpetually indexed, permanently attaching that user to groups they've left. These links should redirect to a non-user-specific page, per group even, that would 1) notify search engines the page they're indexing is no-longer valid and to expunge; we expect privacy that when we leave a group there won't be a never-ending attachment to it. we probably left for a reason in the first place! 2) disassociate the page from the user, further promoting this privacy