As I said, I use the iOS version 99.9% of the time. I've never seen anything like that there.
OK, I just looked at my Settings->Messages and see I have "Send Read Receipts" turned off. Can't seem to open that link you provided, maybe that's what it refers to?
Yes, you have your iPhone (guessing that's what you're using) set for ultimate privacy with texts.
The page shows how to set both iOS and iMac to not send receipts. I now have both set for sneak reading. har har