it is not that you cannot make money but there are times when an understanding of this may save you some financial embarrassment.
yes the market's job is to transact and if the there are a large number of orders at any price-be it stop loss orders or any others-it will seek them out. this is why markets often break extremes [high/lows] only to reverse. that why once the trend is obvious, you get some movements, which is because of the market doing it's job, but is branded as some sort of cleaning up of the weak hands. the market cannot be blamed for this any more than you can blame a bullet train for running over those that stand in it's path. as the trend gets extended expect this kind of movement and take full advantage of what the earlier traders unwittingly have gifted you....