You are making excuses for your assumptions by piling on more assumptions.

You're misusing the word assumption. I don't *assume" that was McGonaggal's reason, I simply judged it to be the most likely and most natural explanation, given the facts in evidence. But yes, I did assume that my initial reading of the text and that Harry also wasn't being mistaken about who told him about Hermione. As I said, I didn't even realize some people saw this bit as a mystery. That's what true assumptions look like, I guess, when one doesn't even realize some people consider it a question.

You may believe that was McGonagall. You may be right. But when you say, "we already know," you are mistaken.

Okay. As I said, when I wrote that sentence, i didn't even realize there existed people who considered this a question. Discussing more about this would probably just be about what the word "knowledge" means.