Not the commenter, but I think the point is that there are simply too many ways to bypass protections. If you want someone to be able to view data, it is impossible to prevent them from exfiltrating it. In many ways it is similar to the analog hole problem with DRM.
You can make it harder to do on accident, or to prevent someone from doing it for convenience (e.g. someone copying data to an insecure location to have easier access to do their job), but you can't stop a malicious actor from getting the data.
They could tunnel over DNS, they could use a camera phone and record the data on the screen, etc. The possibilities are endless.