The mere idea of making money by destroying other people's lives is foolish to me. There is no reason banks need to make millions or billions of dollars in profit. Tax them heavily and return that money to the public through public assistance programs or the arts. We gave them our share, it's time for them to return it.
NO, a U.S. bank tax is not justified to re-coup taxpayer bailouts, because only the banks that received a bailout should repay the money, and they should do so in the form of loans, with interest. Calling it a tax is thinking about the bailout in the wrong way. Rather, the banks should repay the money, without calling it a tax. An additional tax only discourages lending an economic activity.