People that lose hope in holding their Bitcoin investment are those that lose confidence in it. Losing confidence in holding your Bitcoin investment it means that you have lost encouragement probably because you decided to be investing on your own without any community involvement because that can really help. for instance, it will be more difficult for someone who is an active member of this forum to become completely discouraged about Bitcoin than someone who is not a member of any community that talks about Bitcoin but just investing on their own personally out of their own knowledge and being their own motivation.
Well, not everyone who sold the Bitcoin they've been holding for a long time did so because they lost confidence in Bitcoin. Some people already had it in their plan that they would sell at a particular time, and some already have a particular amount of profit in mind. There are even those who sold because they needed the money for emergencies and other stuff like starting a business or paying for tuition.
Selling bitcoin is not as bad as people make it out to seem in my opinion. An investment can be used for many different reasons.