There are probably a few different kinds of people selling their coins, the first type are the ones which are panicking, they are seeing the price going down again and probably that was enough to scare them, then you have the speculators that do not really care about the health of the market and only care about the profits in their pockets and finally you have the smart investors which care about the technology and invest long term but that are moving their money to tether or fiat to protect themselves.