This is very true and I agree with him because people who bought at the ATH will definitely be in a temporary dip and prices that were before the ATH are deep because they are below the ATH as that's the top prices which price is hoping to attain again after it must have gone below that price.
But for those who invest with a long term view, they always have nothing to bother about in times like this, because they will mostly consider it very temporary and have little to almost no effect on their portfolio, but the short term guys are the once who will have a lot to bother about this kind of deep. So yeah CZ was and is right.