Just a few reasons:
So price just goes up or down does it? What about sideways?
Warren Buffet isn't a day trader, he's a buy and hold value investor.
How can you have proper money management when you don't know where your squeal point (stop) is?
I'm firmly in the "Cut your losses and let your profits run " camp. Hiding a loss with a hedge is still a loss in my book. Drawdown = loss.
Trade management is the most important part? I disagree. Psychology is in IMHO.
Not taking a loss screams of ego and a trader that must always be right. It is not about being right or wrong with a trade, it is about probabilities.
Lastly, a trader that is a day trader and holds a loss for 3 months?? I think that is called "position trading"
FF journal: Peaks and Troffs