The absence of scientific arguments against evolution points out the autodeterminacy in the conclusions of a system of thinking. This determinacy began to be a problem in philosophy (after Kant) and proceeded into historical and natural sciences, and, especially in the '20s and on, in physics. This determinacy comes in the form of a limit: the tool finds only what it is designed to find.
When in human thought the starting set of postulates or assumptions are adopted, no refutation to any of its natural conclusions exists, theoretically, because the assumptions stand. No non-Euclidean geometry--it's not geometry. And the irony of the school board's curriculum is that it forecloses criticism from without.
This treats the question foreclosed as to what constitutes scientific knowledge. But more than that that only this kind of scientific knowledge is necessary concerning questions about origins and descent theories.
This is why it is always safe and comforting keep from venturing out of one's own field.
The trouble with the Ohio situation and others like it is that those convinced of the importance of the IDist assumptions want to change science to include it. It isn't science and the whole point of it is that it isn't science. The scope of science isn't limited in the way you describe. It is sufficiently large to accommodate all sorts of fields.
The IDists are not satisfied with exploring the world with new assumptions and then disseminating the findings. Probably, because they don't have any findings. They made the assumption that an "intelligent designer" designed life as we know it, and conclude that evolution must, then, be wrong and should no longer be taught in the schools. The comparison to non-euclidean geometry is at most premature.