I believe that this may not be a mistake. Calling informal language inappropriate may be a ploy to keep the knowledge of political action and scientific discoveries out of the hands of the masses. Dear Miss Grammars, My instructors and teachers tell me in their comments that my writing is wordy and unclear. In their comments they tell me I repeat myself. This results in unnecessary confusion and annoyance on the part of the reader.
Readers find wordy papers difficult to follow.
Don't be afraid of wordiness in drafts. Later, in revision, go through your paper carefully, cutting unnecessary sentences, phrases, and words. Have confidence in your ideas. Many people write wordy papers because they are trying to make their ideas sound important by using long words and intricate sentences. They think that their writing must be complicated to seem professional.