Consider, do they ever go on explicit websites on that computer? No? Because they know that's surveiled while a personal computer for the same purpose is not. As I said, people do know the difference and might do light personal things like googling something unrelated to work but wouldn't do e.g. banking on a work computer. If they do, well, it'll be their fault if they ever get fired for doing so.
The fact that you don't believe people who don't share your same opinion on mixing work and personal stuff are somehow not "real" is part of the problem.
The fact that you don't believe people who don't share your same opinion on mixing work and personal stuff are somehow not "real" is part of the problem.