It is illegal, you’re right, but they want to destroy the legal definitions of many things so that they can write new ones. So suddenly, teaching kids about how their bodies work becomes “grooming”. Being anything other than a straight white Christian male makes you a “sex offender”. Reading anything other than the Bible to kids is “indoctrination”, and so on.
They’ve spent many years and billions of dollars studying the power of language and ideas. They have framing the issues from their perspective down to an art form. If you control what words mean, you control debate and democracy.