Parent freedom of choice for what their own children will learn. Method and content of instruction are vitally important to parents. Many options exist. Parents have rights endowed by their Creator to know those options and the consequences of those choices. A right government exists only by the consent of the governed.
Consent exists only when the parent knows the whole story and agrees to it.
You are the parent. It is not censorship for parents to direct the learning of their children. Without an effective way to express disagreement, any consent is a rubber stamp. Approval that was manipulated by the withholding of information is evidence of a system that is dominating the people instead of responding to the people. When the government leads the people, the people are in harness to the government.