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.
The funny thing is that I never even thought about it, it was my first real email account. But ever since then i've been a vigilant anti-read-receipt person and to this day disable clients from replying to them whenever possible.
Those things annoy me too, but thankfully it's been years since anyone sent me one (unless my mail clients have been silently reporting back to people other than the NSA, of course). I assume the read receipt request button has been made harder to find in newer versions of Outlook or something.
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).
I don't use Outlook; what I mean is that it seems that other email users aren't sending so many read receipt requests for some reason (such as changes to Outlook's user interface). Either that, or I correspond with a better class of email user these days.
