Personally, I can’t imagine calling somebody a loser, but in my head I have a very clear idea of what a loser is. To me a loser is anybody that, in spite of the opportunity to do so, doesn’t take any control over their own life, doesn’t take responsibility for themselves, and blames others for their failure/lack of success. Such people can become marginally successful, but they’ll always be losers, because they’ll never get what they want from life. To me, this idea seems very similar to what he was getting at.