We'll have to disagree about this motorway. I use stop losses precisely because I know I can't predict the future. If you don't, and it works for you great.
However for most people expectation does equal hope as you'll notice 10, 20, 30 times a day if you read the ASX forum.
Back before the Nasdaq crashed a comprehensive survey in the US showed that of those people who met the criteria of trader only 10% came out ahead of the market year over year. And this was in a bull market. Unfortunately the surveyers didn't go into trading techniques or if they did they didn't publish.
However amongst the people I know who consider themselves traders (either part time or full time) those who actually implement stoplosses would comprise about 10%. Hmmmm.