There are four categories of people who are selling right now:
1) Those who are freaking out because they believe Bitcoin is entirely downhill from here
2) Those who are freaking out because they are relying on cashing out before the market recovers to pay the bills (over-invested)
3) Those who are emotionally weak and are panicking solely because their coins' value is decreasing
4) Those who are day trading trying to make a few bucks off the market panic
I think a large segment of the market right now is a mix of categories 1 and 4. They think there is potential for growth, but we're still (even right now) overvalued from the bubble. The price
will reach these levels again, but it's too high, too soon, so it's a good idea to sell.
I'm not saying I agree, but these people do exist, and their reasoning is valid if you make certain assumptions. (Interest and volume are way down, supply keeps increasing, and we have significant regulatory hurdles ahead.)
you forgot option 5) those who are not daytraders, yet are selling to buy back lower.