The talk of representing everyone's belief equally misses the point. Education in this country (for the most part) is career training, particularly math and science education. Students take physics courses and learn about Newton's laws of motion, Kepler's laws of planetary motion, Boyle's Law, the laws of thermodynamics, flow rate calculations, elementary electrical theory (hey, what's that funny word doing there?), friction, and so on and so forth... not because it's promoting society's common beliefs but because that's what employers or university departments expect students to know. They need to apply that knowledge in real life, in the workplace. There are people who still don't believe in the conservation of momentum (quacks with perpetual motion machines) but we don't give them equal time in physics classes: not because they're wrong but because they're not useful to someone trying to get into an engineering program at Local U.
And so, in biology, we can't afford to give equal time to every alternate idea. Students already barely have enough time to learn rudimentary science in high school. If these kids intend to pursue degrees in the biological fields, including medicine, ecological studies and the emerging genetics fields, they need a strong working knowledge of elements of evolutionary theory. The theory meets practice in the real world in those vocations and you are unfairly hamstringing these students by wasting time on subjects that will not advance their careers.
Now, if you think the nation should be concentrating on training students to be pastors or missionaries in lieu of scientists, doctors, nurses, or lab technicians you could argue toward providing courses that teach all the various beliefs our society has about the origins of life and diversity... But it wouldn't be a science class still. Be honest, make it a "History of Cosmology" course or something.