You do you, but you have posted this in altcoins and using bitcoin as an example of fundamentals. Majority of other altcoin don't hold a fraction of bitcoin fundamentals, and actually majority of them are just tokens, not coins at all.
So what's the broader economic context for a shitcoin you think? Why wouldn't people sell their shares if they see crash incoming, because even if you don't trade bitcoin, it's not like holding has been a good option for most altcoins in the past. And as markets are fluctuating insanely, many people are just making money buying and selling them,
I am not selling either tactic would be better, but fundamentals of most of them is just trash and snake oil.
I would say he is right, but at wrong place. He is right that we shouldn't sell bitcoin at this moment, it is going to be great, I believe in it and I think some of the other higher alts too (like ETH or BNB or SOL whatever), but when it comes to shitcoins that you are talking about, you are right that selling those and buying bitcoin would be smarter decision right now.
Yes, I believe we will go to bull run and yes I believe some of those shitcoins could even go up, but we do not know which, so what we are holding could crash, whereas we know bitcoin would go up. So he is right about what he is saying, just not at the right place, this should have been opened up at bitcoin discussions or something, would have made a lot more sense, or even speculations would be better.