The same reason you would posit the unproven theory/religion/belief set of evolution.
Evolutionary biology is a field of science...has been for over a century. It's the unifying framework of all the life sciences. Every scientific organization across the world that has gone on record has strongly supported teaching evolutionary biology in schools.
Why would you think your personal opinions and beliefs should override all that, especially given your lack of qualifications and expertise in the subject?
The point being your preferred theory/religion/belief set is not any more proven than my belief set yet there is evidence for both so, produce all the data for intelligent design & all the evidence for evolution and allow the student to form their own opinions/beliefs because in the end evolution is nothing more than opinion...a theory... a belief set, and I am sure you would say the same of those that hold the opinion/belief of intelligent design.
So let's pretend you're a school administrator, charged with setting the school's science curriculum for the year. As I noted earlier, evolutionary biology is a field of science...has been for over a century. It's the unifying framework of all the life sciences. Every scientific organization across the world that has gone on record has strongly supported teaching evolutionary biology in schools.
Creationism on the other hand has no such support among the scientific community (not one scientific organization has supported teaching creationism in science classes) and hasn't contributed a single thing to science for at least 150 years. The US court system has ruled that teaching creationism in science class is illegal and unconstitutional.
Given all that, why in the world would you start teaching creationism in science class? Because some anonymous guy on the internet says you should?
Can it be proven that the earth is round? Yes...I rest my case...You cannot prove beyond doubt that evolution is anything more than a theory it cannot be proven as fact anymore than intelligent design. The earth being flat however can be proven without any doubt.
Other than the fact that we see populations evolve, all the time, right before our eyes. It's so trivial of a process to observe, we can even give students experiments where they can watch populations evolve.
Sounds to me as if your fear that your theory will fall on it's face keeps you from entertaining a different worldview.
Why would I be worried about anything like that? There's absolutely no indication that evolutionary biology is waning as a field of science. If anything, it's been gaining momentum over the last few decades. The biotech industry is booming, and evolution is at the heart.
Intelligent design does not have to presented with religiosity other than that their is a power greater than man that created all that we see.
Even the ID creationists at the Discovery Institute (the people who came up with the idea) don't advocate teaching it in schools. I agree.
Are you afraid to let people decide for themselves based upon all the unproven data or just the unproven data that you prefer?
It's a waste of class time. As I noted earlier, we don't do this with any other subject and there's no reason to do it here either.