the altcoin market is very affected by the current trend, the higher the profit opportunity the higher the volatility, it is unavoidable, bear markets are normal in the market and that is a common thing, maybe only big coins are able to recover faster when a bear market occurs.
Yeah, recovery phase for different altcoin is always different hence we cannot have any generalized opinion on all altcoins while investing with them. It would be better if you go investing at the beginning of bull run and should book profits by the times of end of bull run; so that we do not need to hold on bearish trend. If you happen to hold on bearish trend then you got only 50% chances for recovery.
You are right, however when altcoins rise for reasons other than a BTC bullish trend, it is because they are actually pumping it from elsewhere, perhaps to create a possible pump and dump, or because some devs want their currency to go down. look good for them to come in to buy and they can sell little by little, this is a strategy that is always applied in all markets, in fact it is something that has been done since the 1800s from the time of Jesse Livermore and Richard Wyckoff who were great market speculators in their time.