If for some reason, it should ever come up...
When I tell you "you said something stupid" or "you said something ignorant", I am not insulting you, or attacking you; I am informing you that you made an egregious error, and pointing out the type and magnitude of that error.
If I told you that "you said something stupid", it means that you had knowledge of or access to the facts, but your understanding, analysis, or expression of them was obviously false or incorrect, given the slightest attempt at intelligent reasoning.
Understand, "stupid" does not denote a simple error, or incomplete argument (that's what the words "incorrect", " mistaken" or "dumb" are for); it requires deliberately ignoring the facts, or drawing conclusions or stating positions that are completely unsupported or contradicted by the facts.
If I told you that "you said something ignorant", it means that you spoke authoritatively about something without possession of the relevant and correct facts.
These are not insults, they are statements of fact.
If I was not certain of the truth of my statement, or if it was a matter of opinion or interpretation, I wouldn't have made it; I would have said " I think you might be wrong".
If I respond to your statement in such a way, it means I have sufficient respect, consideration, or hope for you; to either correct you outright, or to give you the opportunity to clarify or correct yourself.
If I didn't have such consideration for you, I would have simply ignored you, trusting that others would do so as well, in the hope that you could not increase the net total of stupidity on this earth.
If you find statements of fact which have shown you that you are in error, to be personally offensive or insulting... Well, that's your character failing, not mine.
Everyone says stupid and ignorant things all the time... Its a basic part of life as a human being. It may be humbling or bruising to the ego to be corrected, but it is not an insult
Personally, I hate being wrong so much, that I would rather be corrected, than to continue being wrong... And am grateful for it when it happens (which is frequently, as, like any other human being, I'm wrong a lot). Every bit less wrong I can be, is just that much less net stupidity in the world.
If I were actually being personally insulting, I would have just said "you are an idiot".