Except that the scientists don't just "say so." Publications have to be peer-reviewed, and there are rivals around the globe to try repeating the experiments.
But then of course we all know what your response would be. "The hegemony of science is a massive conspiracy funded by Illuminati." Every evolutionary biologist knows deep down that evolution is wrong and creationism is right, they are just too timid to challenge the institution/have their evil agenda in keeping the whole world ill-informed.
That was brilliant.