It's true, but the opposite strategy - sugarcoat the truth to avoid raising uncomfortable questions about the status quo - also breeds mistrust in education and institutions. All we can really try to do is present our best view of the truth, with all the uncertainties around that. Does smoking cause lung cancer? That certainly appears to be where the weight of evidence sits, and it would be a lie of omission to avoid saying so. Should you quit smoking? That's up to you.
That's true. The alternative is a bland world of platitudes where no one ever says anything and all the conflicts are fully made up (as in the case of over-the-top villains for a cartoon purportedly about being good stewards of the environment).