This request arises from student feedback..... When posting a comment into the Post Text widget as a student, the *default*  seems to be for central alignment of the text. 

Students have given me feedback that this is hard to read in gallery view.

Even though students may have access to the buttons for left or right alignment of text, so they can change it themselves, it would just make more sense if there was an institution setting to specify left or right side justification of text as a default.