No investigation no right to speak is a core part of MarxistLeninist thought as it has evolved. Naivete is not "a sin" but if you haven't researched a topic you shouldn't speak on it.

As Chairman Mao put it:

Unless you have investigated a problem, you will be deprived of the right to speak on it. Isn't that too harsh? Not in the least. When you have not probed into a problem, into the present facts and its past history, and know nothing of its essentials, whatever you say about it will undoubtedly be nonsense. Talking nonsense solves no problems, as everyone knows, so why is it unjust to deprive you of the right to speak? Quite a few comrades always keep their eyes shut and talk nonsense, and for a Communist that is disgraceful. How can a Communist keep his eyes shut and talk nonsense?

It won't do!

It won't do!

You must investigate!

You must not talk nonsense!