A backdoor is a mechanism for someone to be given access to an internal system, or internal data. In the case of data being "pushed", it most certainly could be

A backdoor is a mechanism for someone to be given access to an internal system, or internal data. In the case of data being "pushed", it most certainly could be done so, and the same statement would remain true. If your comment was true, you would also assume data handed directly to authorities in criminal cases where subpoena's are issued would also be ruled out, but we know that information is handed out to authorities as required by law under subpoena.