Many people today say "The Big Bang wasn't witnessed and can't be repeated, so it isn't science." The truth is the singularity event isn't a hypothesis itself, but a conclusion drawn from dozens and dozens of other testable experiments and repeatable observations. It's a model of the universe built on a mountain of facts. That said, the theory does make unique, specific predictions that can observed, verified, and repeatably tested in their own right - including the first light from the dawn of time that you can still observe yourself today.   

If you truly believe that the theory is bunk, I invite you to come along and see for yourself how it was conceptualized, what data supports it, and what tests and observations can still be repeated even today.