When people talk about taking their kids out of the public school system based on the ideologies- they mean evolution, possibly "contraceptives work", and maybe even CRT which just validates that racism existed throughout the entire history of the United States, eg disliking how schools teach "the Civil War was about states rights over owning slaves", the HIV/AIDS epidemic was a colossal failure of US policymaking, and that racism didn't end somewhere between the 70's and the 90's.
This is not what CRT teachers, CRT teaches that people are explicitly responsible for the actions of long-dead ancestors with the same skin colour as them.
Remember, the federal government sets the legal drinking age at 21. Are you going to argue this is a bad thing because the federal government could in theory force states to allow drinking at the age of nine?
If the federal government forces teaching creationism, we have bigger problems. If a state wants to receive federal education dollars, it must behave. Simple as that.
School districts are a vestige of our racially segregated past and unfit for tomorrow's children.
I don't think that's a persuasive argument. You are assuming a (by your own admission) hypothetical situation which is different from where we are now, and ask "But if our situation is different, would your position change?" Well, of course it will. Would you rather want people to keep their positions when the situation changes?
Besides, if the kind of people who'd teach creationism get hold of the government, they wouldn't give a damn about what their predecessors thought of public education. Nobody's going to say "I was planning to teach the nation's kids that the earth is 6,000 years old, but my neighbors fought for the rights of parents to teach their kids that the earth is 6,000 years old, which showed me the error of my ways."
This is less of an argument for charter schools and more of a line of questioning to figure out the motivation behind people's stances. Are people against charter schools because they think other people's kids won't be taught the stuff they want, or do they believe the state should have supremacy over what can be taught using public dollars, regardless of the content?
It's easy to make the argument against charter schools when the "majority" of people supposedly using them are using it for "bad" reasons, but what if the situation were reversed? Would you be pro charter schools in a jurisdiction where the public school system is shoving young-earth creationism down student's throats or refusing to teach sex-ed? Does your support for charter schools hinge on whether they're being used to teach "bad" things to kids, or do you believe whoever has political control over the school system should be able to dictate what kids are taught and parents cannot opt out?