It seems you don't understand what science is about so I'll try to explain to you in simpler terms what the difference between science and creationism. Science is about a methodology that actually works and produce tangible results (cars, computers, Internet, etc...) whereas creationism is about a methodology that has failed to wield significant results for thousands of years. That's why they don't belong in the same class.
Of course, you could disagree, but then your objective shouldn't be about integrating creationism into science (since you seem to think your method is better), but create this "creation science" with the fundings from churches and get better results than the current science. Since you believe your method to be superior to those of the actual scientific community, you will get better results and be able to finance yourself after the start.
It's the scientific community that decides what goes into science class, not the church. The reason science is taught at all is because it wields results, if it was just "thinking" like usual, then how come the church (that is supposed to know the "truth") didn't make those kind of progresses all those centuries when their dogma was taught at school?
If you think the scientific community is wrong, there's an easy way to prove it, set up your own scientific community with your church and get better results, then you will be able to replace science class with your brand of "science". It's obvious that your idea of science is different from that of the scientific community.
It's amazing that when creationists are asked to do the work, the only thing they seem able to do is whining and find excuses why don't want to actually do the work scientists have when they want to be recognized. If Einstein, Lemaitre, Bohr and the like had reacted this way when their theories were first rejected, they wouldn't have gone far. They didn't go to court and tried to convince an ignorant public through churches, they just kept on working and that's the difference between actual scientists and creationists.
We don't teach creationism the way you want us to for the same reason we don't teach flat-earthism. Not only there's no science behind it, but it contradicts science. Science is not just about "ideas" but about modeling reality. As I've already said, why are creationists not doing the work scientists had to to get accepted? Creationists are first when it's about deceiving the public but there's noone left when you have work to do...
Tell me, should we teach Astrology in physics classes? What we teach in science classes is supposed to be SCIENCE. The problem with you creationists is that you're all for teaching your beliefs but noone's there when you are supposed to do the work. Every scientists had to do lots of work to get their theories accepted but somehow you guys think we should bend over backward to satisfy your primitive beliefs when you do none of the work required.