He is obviously wrong and we do not have to make too much of an effort to prove this, however this give us insight about his state of mind, it is likely the user you quote above is actually saying that if bitcoin went down below 30k then he will be done with bitcoin forever which means that from that point on it will not matter to him what bitcoin did as he will not come back to the market, when you read his comment in that way it makes more sense even if we do not agree with it.
Bitcoin goes down below $30k but at what price it will find the bottom?
I am tired when people raise their calling in bull run and change their minds with lower lows in bull market.
If he plays the downwards movement smart he just tries to buy with a limited budget in predefined steps all the way down. I wouldn't think Bitcoin goes under $20k because there is just too much buzz around it and too much at stake with all the institutional investors that are now on board, but I can see Bitcoin hitting the 20s.
Would it harm Bitcoin in the long run? I would say no. Gold hasn't died either when it dropped dramatically and gold had ver volatile times.
I believe the worst scenario is when Bitcoin falls to $20k to $21k but if I don't have money to buy that dip when it happens, I am fine and don't panic or regret. I will hold my Bitcoin and wait for the bounce to $50k. I don't want to lose my Bitcoin with the bet at $20k to $21k.
It is very possible bottom if Bitcoin crashes again.