Science has spent a good fourty years encouraging scientific writing to be more straightforward and with a real authorial voice.
This is not to say that clearness of expression is not longer desired. It is to say that expression should be to the point.
It's disappointing that you had this experience. Especially since a more direct writing style allows more content per page, and scientific writing is ruthless with page limits. So this teacher is not preparing you for the 'real world'.
In business, communication matters even more. People spend days 'workshopping' (cooperatively editing) a single page 'pitch' (the reasons why investors should fund the company).