Okay. Professor McGonagall knows that Harry Potter is the one with the power to vanquish the Dark Lord, that he is marked as the Dark Lord's equal, and that he will have power the Dark Lord knows not. (She has, in fact, heard that Prophecy spoken in the terrible hollow echoing voice of Sybill Trelawney.)

Harry isn't acting like a normal eleven-year-old, or any kind of eleven-year-old, and Professor McGonagall has noticed that as well, in as many words.

That's all. If you think, under those circumstances, that the boy ought to be given the back of your hand and told to shut up, you're welcome to write your own fanfiction where that's what Professor McGonagall does. The further consequences seem predictable enough. The thing is, in my story, Professor McGonagall can see that too.

I honestly have no idea how that has anything to do with what I'm saying.

And I read all the books, and watched the first six movies. I know what the prohesy is.

You honestly can't see how knowing someone is the chosen one destined to save the world from the evil one and who quite possibly already stopped a war impacts on the likely behaviour of a character? Implied via that same knowledge is that Harry has the favour of McGonagall's immediate superior.

It should be overwhelmingly obvious to you how this information is relevant to what you are saying. Any judgement made without considering this context is absurdly ill-informed.

As in she knows they need him, so she's making an extra effort to make him like her, and by association, the wizarding world.