alt Hacker NewsThis kills accessibility. You wouldn't even be able to select text unless the page implemented that feature itself. Screen readers would have nothing to work with. No high-contrast mode, no translation, no changing the font size, no reader mode........
Unfortunately none of the things you listed are what page vendors want you to have. They'd very much prefer you didn't. On the web, they're just too hard to prevent, so most don't bother.