I want logical positivist schools that only teach scientifically verifiable truths about objective reality :)

But seriously, you make a good point. I think the number of people who agree with the claim is important, but there is perhaps a second issue in that some people claim that certain information can produce irreversible personality changes. If advocating homosexuality turned people gay (and shared environment does affect the prevalence of lesbians) then this causes a permanent hit to the utility function of a homophobe, whereas if some one wants their child not to share their toys ( because that's communism, maybe?) then the child could still change their mind after they leave school.