thus . . . putting "theory" after each mention of "the Big Bang" would be . . . CORRECT.
Actually, the evidence so strongly supports the Big Bang Theory, that the word "theory" does harm to the science behind it. The principles of the Big Bang have been confirmed by a wide variety of observations. No other theory comes close to explaining observations of space. In many scientific circles, the Big Bang is now called "Standard Cosmology."
The problem is that due to his other statements we know he's pandering to those who like to confuse the vernacular "theory" with the scientific "theory" to try to discredit the theory.