I see a lot of topics talking about why bitcoin did this or that. Sometimes there are clear indicators as of why but many times it simply happens. Coincidence, trading bots and simple TA can affect the price and create a snowball effect easily.
Imagine 3 whales with 1000 btc each decide to sell bitcoin and by chance they do so at the same time. Of course the price will tank and people will wonder why, bots will follow and so on.
It's basic demand and supply kinda thing. Only bitcoin is limited and not all people own it. Plus, FUDs, Analysis chart, famous person saying not to hold, etc are some of the reasons why the price changes at times. Bitcoin always has some kind of issue or news about it that affects it price, whether it be small or big news, which naturally affects the perception of bitcoin owners whcih then makes them sell the coin all of a sudden.
He's right, there isn't always a clear reason for the price increase or decline, it happens naturally in the market, at least for a mere $100-$500 in a day.
But for the price changes around $500-$1000 within a day or couple hours, there must be a reason why it happens obviously, just like one day after the Bakkt futures launch, bitcoin price fell more than $1,000 so people speculate because of that. Not a basic thing like demand and supply, because bitcoin price will always increase if that's the case.