Nothing and no one forces you to cheat, it's a choice; an admittedly common choice, but then so are a lot of immoral acts like lying and stealing. I'm not saying that online tests are a good idea because we have to live with the sort of people who cheat, but lets not pretend that this turns "good people bad".

Good people don't need excuses to be good, and don't respond to excuses to be bad... if you want to simplify to that extent.