He means corporate income taxes. Dividends come out of profit, after income taxes have already been assessed.
Put another way: If Acme Manufacturing pays an employee $50,000 in wages/salary/benefits, that's an expense. It is subtracted from revenue, to calculate profit.
However, if Acme Manufacturing declares a $50,000 dividend, that is not an expense. It comes out of profit, and was taxed at the corporate income rate -- up to 39.6%.
I forgot to add: and then the dividend distribution is taxed at up to a 15% rate on the individual shareholder's return.