Those who panic over dips are people who failed to invest with only their discretionary income. If you invest properly with only part of your discretionary income and your plan is to hold for long, there is no way you will panic because you know that the price will always correct and put you in good profits with time. It has been emphasized several times that people must think long term after investing with their discretionary income. Failure to do this will only make you to panic over any price drops and that is highly discouraging and not a good place to be as an investor because your peace of mind should not be dependent on the price of Bitcoin.
All that you said here are very true, the brain behind panic selling boils down to investing what you cannot afford to lose, so when the price of bitcoin is not going as expected, they will start being emotional about it.
This is why I blame ignorance in the case for newbies because they don't even know that investment in bitcoin is done with discretionary income alone, not any income they have.
Those that are aware of the nature of Bitcoin and are still panicking are doing so because they are not doing it long term, they thought they would just buy and pull out in no distance time once it rose in value, but in the process it went the other way around, and most times they feels like they don't have much time to wait, which is not the best way to approach bitcoin investment.