As shown in the changelog, the bug was filed by a user @amplifiedit.com, and was seen as a worthwhile bug to fix by Brian Malcolm "Taking ownership as the client team in BVE will work on this item"[0]; however, it was stalled for nearly 3 years until Eric submitted a patch for it[1]. While Google thinks it's worthwhile to fix, Microsoft is trying to have a faster-than-usual rise in adoption for their new Edge which is based on Chromium, so that means fixing as many things as possible that their business/EDU customers complain about.

BTW Google already allowed MDM (device) admins to disable devtools, but everyone involved in the issue also wanted it to disable view-source since it allowed students to look at the HTML.

0: https://bugs.chromium.org/p/chromium/issues/detail?id=895462...

1: https://bugs.chromium.org/p/chromium/issues/detail?id=895462...