Because we are talking about science, not politics. There is only one "side" of this which is, by virtue of the verifiable evidence supporting it, scientific in nature.
If the "other side" were mentioned, honesty would require the disclaimer that no verifiable evidence supported it.
When geographers and cartogaphers draw up maps and globes, they do not invite comment from people who believe in a flat Earth. Just because something is "another side" doesn't mean it is valid or should be heard.
I notice that the press makes this mistake often, to the point of, after a murder for example, getting the killer's "side of the story".
What about the Gay argument and the absence of science supporting their claims, or is that off limits.. I know the answers to both questions and I don't believe I need to be lectured.
Frankly, I could care less about the Darwin argument, I am just tired of cleaning up the BS my kids have been taught in the public school system. I would just love ONE TIME to shove an absurd totally religious concept up the liberal's ass, assuming there is room!