There's an extension called "Don't fuck with paste" which disables intercepting paste, not sure how. You have to remember to add sites that you do want to intercept paste (mostly rich text apps) to the whitelist.
Firefox ignores the right click overrides if you hold down shift. I'm not sure about text selection, but there's probably a way to do that as well. I haven't found a bypass on Chrome yet, though.
As for copy, I often find that the less common copy/paste commands (ctrl/shift+insert) still work when control+c/v have been intercepted. Sometimes adding an extra key also works (ctrl+shift+c). I theorize that this is because a lot of the times copy/paste is disabled, the incompetence of the people deciding on and building in the anti feature drips all the way down to the JS implementation.
> I'm not sure about text selection, but there's probably a way to do that as well
Sure. It's usually some CSS rule that can be easily turned off. These things are still extremely annoying though. We should not have to fix people's sites.