Because according to him Bitcoin is a small number of people who have a lot of Bitcoin. They can easily go down on the bitcoin market if they want to.
Example: Cz. Craig wright & Michel Sailor etc.
Looking forward to the well thought out opinion of the experienced in this regard.
I don't think his assertions are correct on this note. This is just a perspective he's giving to it but he hasn't really go deep in the whole Bitcoin technology. Truth of the matter is, Bitcoin is not owned or controlled by a small number of people like he portrayed but Bitcoin is a growing technology that has developed a large number of individuals from across the globe. Because of the anonymous nature of Bitcoin and the crypto world, it becomes very difficult to simply put that Bitcoin is owned by the above-mentioned names. That cannot be the case.
There are an estimated number of 400 million plus owners of Crypto wallets with over 219 million of those numbers owning Bitcoin private wallets and the trading value of 17 billion dollars traded in just 24 hours as of August this year Source.
So I think it will be too simple to come to that assertion about the number of those who control the decentralized market. Although, your friend has all the options to stick to his choices, but if really he's that stinkingly rich and he's an investor, he would love to have a major share in the Bitcoin market.
The advantage of cryptocurrency is that it is decentralized; it does not have a limited authority; only he is running it, but everyone works together. It is true that CZ has a large amount of Bitcoin, but he simply cannot munipulate the market; rather, he needs a large amount to munipulate the market. And in a decentralized world, it is not appropriate to look at the capital of only a few people and say that these are the people who control the market, but CZ says that the market cannot be predicted. They also have this idea that the market cannot be controlled by single-buddy people, but many people work together under cover.
I hope now OP's friends understand what the truth is.