I actually agree with this analogy. However, Bitcoin is not stock - unless now, after first calling a currency, then a store of value, we magically transition to calling Bitcoin a stock-like asset.
But people would continue to buy Coke. And Coke would continue to make a profit and Buffet would look stupid when the company did well, even if he was able to cause a 10% dip in the stock. It is unlikely that the world would stop drinking code because Buffet said he didn't like the stock.
Bitcoin on the other hand, has no profits and only can be successful by having everyone agree it is better to own than gold. So if Musk's opinion is followed by many other people it will bring bitcoin down for a long time.