Honestly I find read receipt requests to be in very poor taste, if not a sign of outright hostility, and no, having them by default is not an acceptable excuse, no more than forgetting capslock on would.
I reckon the correct way to handle these receipt requests is to configure the mail client to send a modified receipt email which also has a read receipt request, and keep replying in kind until your correspondent gets the message (or the mail servers break down due to two bots telling each other that they read the notification that they just read each other's mail telling them they read their mail, of course).