Last year, a lot of people learned about Bitcoin but did not learn what is actually the use of it. Some of them knew Bitcoin as a source of a large money where they will just invest and earn profit instantly. Simply to say, they just joined the hype train. That's one of the reasons for the price to go up.
When some of investors pulled-out their money during the Holidays, BTC price went down and these people who just jumped in the hype train also pulled out their holdings. Now, Bitcoin price went down and these people stopped investing with BTC.
Your opinion looks erroneous on many fronts. Basically, you forget that when you sell your coins, there is always another side or party to the trade. For you to sell the coins, someone has to buy them from you. In other words, you can't say that those who joined the hype club first put their capital into Bitcoin and then withdrew it. They didn't pull out the money invested and thus got stuck with the losses turning into long-term investors aka bag holders. They are the ones who bought from very few who actually jumped off the crashing train in late December.