Most rich people like Bill Gates and Warren Buffet are against investing in bitcoin or cryptocurrencies in general because of the huge risks due to heavy volatility. I'm very bullish on bitcoin and cryptocurrencies, but it's indeed a huge gamble. "Moon" and "lambo" gains aren't guaranteed. We're just pretty much speculating and hoping that it would indeed rise to very high prices.
I guess what bill gates and warren buffet trying to say is cryptocurrency is not a trusted due to high volatility rate. Bill gates who is known for richest man alive after founding microsoft has the ability to control the market, figuratively speaking bill gates can own a large portion of share in the cryptomarket if ever.