That's called censorship.
No, it isn't. Why does everyone call everything censorship? Censorship is the suppression of speech. Saying "No, that is false" is not censorship. I'm not suppressing your speech.
News organizations don't put every person with an opinion on the air. People who claim that world leaders are a race of sentient lizards from the core of the earth don't get air time to discuss politics. Because they are clearly not adding to the discussion. That isn't censoring them, that is not giving them a platform.
People are entering the debate all the time. It's disingeneous to shut down conversation from now on because you've settled on the matter.
So should we discuss whether it is obscene and monstrous to cut open bodies for medical research? Back in the day, that could get you killed. But, strangely, I don't think there is much discussion about whether bodies donated to medical science should be legal or not. We seem to have settled the matter.
What about the discussion of whether we should ride horses or drive cars? New people have entered the discussion, so maybe we need to go back and discuss highways and whether or not we should build them.
Or, maybe, new people entering the conversation DOESN'T make much of a difference, when the matter is actually settled. Gravity is real. The Earth is Round. Racism is a terrible evil. Don't need to really have debates about these things, unless you've brought some gigaton level evidence to challenge them.
Kid asks questions, you don't shut them down - you attempt to educate. It's also non scientific to not allow an idea to be challenged.
A few points.
1) I don't care if I'm non-scientific, I'm not a scientist. And even scientists don't just sit and take any and all challenges seriously. If you wrote to a scientific journal claiming that the Earth is flat, because you don't see the curve, you won't get published. No one is taking that challenge seriously. You need massive, paradigm destroying evidence, not "I don't understand how this works, therefore it must be wrong"
2) Children are very different in this regard. Firstly, children often don't know, which is why we attempt to educate them. But if a 55 year old man, who is on a major platform like Youtube is talking about the flat earth, or about how birds are fake to disguise spy drones, I don't need to educate that man. Other people have attempted to educate that man. The problem is not a lack of attempts to educate him, but a lack of willingness to be educated. Most children aren't entrenched in their beliefs. They will be willing to listen, and to accept the evidence for how it really works.