Even Greener Pastures

It reminds me of what linguists like Noam Chomsky have said, „If someone has to teach you something about your own language (native language) the odds are about 100% that what they are teaching you is wrong. That´s why you have to be taught it. Because it´s NOT your language.“

Stackexchange has an English board (and boards for everything from chemistry to gameboards) and people debate ridiculously silly nuances in expressions and words like this. And there are no real „answers“. Native speakers disagree constantly on things. I see this on the german.stackexchange board all the time. The native speakers can`t even agree on things because languages are fluid and change all the time.

Steven, I really can't agree with either Chomsky or you.
Native speakers make mistakes all the time. I keep reading and hearing things like "Salami mit Nüsse" (should be: mit Nüssen) or "Ich verbinde Sie mit Herr Müller" (should be: mit Herrn Müller). Now, granted, the German dative may become as obsolete as the genitive already is - in time. But at the moment, leaving out the dative ending is still considered a mistake and will get you bad marks in an exam. (And so would "das brauchst du zu tun", by the way.)
Plus, I think you're forgetting that you need to have an extremely good grasp of a language in order to decide whether or not something might be considered a "trivial" mistake (if there is such a thing). For a language learner, this is obviously impossible.

Also, please remember that many, if not most people here are quite interested in this kind of question.
I would therefore ask you to kindly moderate your tone a little.