Because data is subject to political interpretation, and while we'd all like to believe that science is noble, objective, and utterly dispassionate, it really isn't - especially not in the social sciences.

You only have to look at the history of "research" into economics, or race and IQ, or genetics and psychology to see how this works.

It isn't even particularly dispassionate in physics. There's a huge amount of politics involved in deciding which ideas and hypotheses in fundamental physics get time, money, and PhD candidates, and which are considered "the wrong choice for a successful career."

So it is not true that if the science is bad it won't get published. A huge amount of very bad science has been published, and some of it has been used to influence public policy.

I can't think of anything that works better than science, but that doesn't mean I'm willing to treat it as a stand-in for religious infallibility.

Objective insight is a constant struggle against external influences, internal biases, and political conflicts of all kinds. It's not something you get for free from science by pushing a magic button and waiting for Revealed Truth to come out.