You are very correct. Those panic sellers should open their eyes to see tomorrow. It is the most unintelligent thing to easily throw away an asset like bitcoin because the price is coming down. But you forgot that at the other end, someone is buying bitcoin from you.
That is why many investors taking an opportunity to panic sellers and telling about FUD which trigger those emotionally weak. Open your eyes that it is the end for bitcoin, it won't lose the value. While somebody enjoying the moment to have more volume at cheaper amount, you are wasting what you have which is late to cut losses. You have to be confident on what you hold because that will be worth better when the price increases.