It isn't they're holding selling & buying because of confidence in bitcoin. Some ppl want to hold because they're sure they'll get more profit but can't wait. One day we're going to need money in emergency situations if ppl can't hold they'll sell. Their confidence in bitcoin doesn't change their mind.
The main reason why many people are always willing to sell their Bitcoin when the price is rising or falling but are willing to hold it long term is all because of confidence. We don't have full confidence in Bitcoin that much. If not, we would see some people treat Bitcoin the way they treat other investments.for example, if someone invested in land, they would hardly sell, even when the price of the land is rising significantly. The common belief would be that the price will continue to rise. So, what I’m trying to say is this: if Bitcoin were treated like other investments, it would be much harder for people to sell their Bitcoin before the time they originally planned to.Another way to prevent someone from quickly selling their Bitcoin is to always invest only what he or she can afford to lose.