It is also important to adapt ones trading strategy to the bull and bear market because what works in the bull market most of the time won't work in the bear market
On the contrary I feel what works for bull market can also work for bear market what it means is to upturn the strategy because for example using RSI to interpret, you have overbought and oversold, likewise for MA can be used for determining the range of market movement bought for bull or bear. Fibonacci and other indicators too can work both ways depending on how you are placing your fibo. It is reasonably so because market don't go move just one direction, it is either bull or bear and it is same indicator that are used to analyze the chart.
It is theoretical and in the practical situation of this, not many people and even myself know how to adapt a strategy to both bull and bear market. The bull market is always booming and profitable, with little efforts you are already getting results. This cannot be said of the bear market. That is why it is always advisable to test your strategy and re-test it with the bear market. But if actually you cannot handle the bear market trading, it is fine you avoid it totally. But in all I agree that what works for bull market may also work for bear market, but it all depends on who is behind the screen (Skill or unskilled).