It disables most other shortcuts too. No fullscreen (F11), no "new tab" (Ctrl+T), no tab-jumping between links and input elements. I usually browse without using a mouse and suddenly got trapped inside this article, since they also disabled "close tab" (Ctrl+W)

I absolutely detest the fact that browsers allow overriding core keyboard shortcuts.

I detest the fact that the browser uses the F-keys for its own shortcuts. We have an a web-app ported from a mainframe app that uses the F-keys for functions the _user_ carries out and users love being able to press F1 through F12 to activate buttons and other page elements. Familiar users can navigate throughout a complex app without the mouse and without continuous, repetitive tabbing.

Overriding the browser should absolutely be allowed.

For some things, sure. No excuse for being able to override to the extent that you can't leave a site without plugging a mouse in. Maybe, maybe, that could be allowed with an up-front confirmation dialog, but definitely not forced.

It comes down to use. The behavior you describe is infuriating and bad-practice. I think we are both right.

It should be something you have to opt into, with one cancellation button not overridable, similar to fullscreen mode.

It's necessary for some things like games and certain web apps. I made a javascript game awhile ago, about guessing the next character in source code, which required disabling Tab.