Torah study

peace. In your post about the Bible, you wrote that you see the study of the Bible as a boundary of Torah study (because of the text, etc.). Why? After all, didn’t the entire Bible come from Moses at Sinai? Why is it Torah study and not history study? What is the boundary?
Another thing: Why is studying the words of a commentator on the Gamma considered Torah study, when that commentator is wrong in his interpretation? That is, let’s say I study Rabbi Chaim on the Maimonides, but his interpretation is wrong. Why is this considered Torah study?