There are two types of Bitcoin Holder,
 1. Short-term holders - those who usually sell their coins and empty their wallets.
 2. Long-term holders - those who usually hold for many years and see their wallet address filled with a lot of Bitcoin.

Perhaps, it was their choice and you know what, it was hard to convince a person to hold when in their mind is to sell when the price went high. You can't force someone to hold if it was not in their mind.