Some may be panicking for some other reasons. Like what if some of them buys bitcoin at the highest rate ? maybe they're just worried that, What if BTC will not reach the same value again ? There's so many reason to human behavior, you just have to understand.
But then people should not be buying bitcoin at all if they are going to be that sensitive, it is just plain logic if bitcoin can grow thousands of dollars in days then it stands to reason that bitcoin can lose that value as well, those that bought thinking that bitcoin can go up forever were mistaken in their attitude towards bitcoin and now they are paying the price in the form of lack of peace of mind and very soon in the form of money losses.