To repeat the OP's point, one of the important reasons is that Berkshire Hathaway is a large shareholder in many banks/financial institutions.
Reference mentioned in the OP pertains only to stocks. Indeed, Berkshire Hathaway's exposure to financial sector is larger, as it holds significant amount of debt and debt-like instruments from that sector.
Bitcoin disrupts the current financial/banking system. Investors in the current financial/banking system don't like Bitcoin. Is this supposed to be news??? It's 2014 guys we knew this like 2 years ago didn't we?