When we fail to teach evolution to our young people, we leave them ill-prepared for the type of instruction they’ll get in college. Secular universities teach evolution upfront and without apology. Students who weren’t exposed to it in high school or who were given just a cursory treatment will be at a disadvantage.
Creationists have been trying to water down evolution in public schools at least since the Scopes trial. And they only pretend to be champions of critical thinking. Their plan is to offer students a choice between accepted, verifiable science and an account based on a narrow, fundamentalist interpretation of the Bible that even plenty of Christians reject.
Yes, it’s illegal to teach religiously based concepts of origins in public schools, but that doesn’t mean the schools all automatically follow the rulings or do a good job teaching evolution. Some teach it poorly, if at all.