Warren Buffett has been a critic of companies that use their capital to buy back stock instead of investing for future growth. He also hasn’t been a big fan of millionaires and billionaires trying to minimize their taxes. None of that stopped him from spending about $1.2 billion to buy back 9 200 Class A shares of his Berkshire Hathaway holding company from what the firm described as “the estate of a long-time shareholder.”   Buffett has famously championed the idea that the rich should pay more in taxes and just this week signed on to a letter calling ...