First of all, there are many different types of banks. There are central banks, investment banks, and a wide variety of multinational corporations that have financial and banking services that are integrated into the global monetary and economic system that defies a single human's comprehension and understanding.
The specific type of bank that the politician is referring to is a depository institution or thrift that is involved with taking in deposits and issuing withdrawals of money. This is community and retail banking, and bank robbers target these institutions as they serve as a point of entry into the global financial, monetary system, and it holds banknotes that robbers want to steal. These people are really not interested in taxation levels set by government. They are much more interested in the banknotes that are held by retail banks.
The politician is not making an effective argument because a citizen is concerned about their checking and savings accounts which are not affected by the theft of banknotes.
