Sounds like the initial part of password testing, and then they either forgot to complete it, or someone came along to fix the later parts, commented them out for testing and never got around to fixing/uncommenting. Surprising how often things that ‘work’ are set aside and no one is in charge of reviewing.
The’logic’ behind it is that if you copy/paste, then the confirmation box is basically useless. If you copied the wrong account of just part of it, your for sure going to paste in the exact same thing without really checking. Not that it’s a good reason, but at least there’s some logic