I can't anything about them criticizing about bitcoin. They are free to do so but I doubt it that they never invested to bitcoin and cryptocurrency. Bill Gates once said that he do believe bitcoin and even said to "buy bitcoin" I forgot the youtube channel I watched it. And about Warren Buffett, it's still a mystery if he's an investor or only giving constructive criticism. IMO, these people just want to give a full blow to the market so that they can short and pump through their publicity and words.