You have a good point! If we can only fully understand the market then we can know the right time to enter and to exit in trading.
And the toughest part of trading is doing the same. You cannot decide on what point is the best to exit by just looking at speculators. Remember that majority of the opinions are biased because they are coming from the bag holders of coins. They want to make profit dumping on people who are coming in new. If you do your own analysis then the older price chart should indicate a good entry and exit point.
There are many information around the internet that are useful in trading of cryptocurrencies.
There are also fake news and manipulative news which one must become resistant and begin to ignore. Then there are shill youtubers who pump their bags of coins.
There are whales who always ready to take the advantage of our unawareness so when they start to spread bad news in market they become so active whoever wants to sell they will be ready to buy, so same as you I got to learn that no need to listen them and selling buying should be done with my own observation and with patience.