In other words: people who missed the opportunity of buying cheap bitcoins and complain about it would be the first ones to waste the opportunity taken if they had been holding bitcoins on their hands during a correction by panic selling all their coins.
Somehow you are right and there is a big chance potential investors would panic sell in this situation for different reasons. But we must also be aware that who really moves the market are the big investors, the whales. And these people don't panic sell because they are unexperienced or can't afford losing some money value on short run. They sell their coins because they profit from market speculation.
The fools smaller unexperienced investors who follow them don't make too much difference in bitcoin's fluctuations.
I think that it's incorrect to make a simple rule off this. I disagree with what OP said because I'm such an example.
There was one case, long ago, when I was very close to buy more Bitcoin very cheap. I didn't because the machine had tremendous fees. Then Bitcoin rose a little and I said I wait, then... poof, too late.
But (much) later on I started putting aside some of coins I've earned (I also sold some, I had/have to..) all in all, I do hold some. And I still think that I could have had much more if I would have bought, back then, at that incredible price.
On the other hand, I expect that most of those telling "I wish I would've bought Bitcoin at X price" never actually buy. So they don't also have anything to sell.
So, as I said, it's incorrect to make a simple rule. There's
more than one category of people telling "I wish I would've bought Bitcoin at X price".