For all thirteen years of my career teaching high school English, one consistent skill that I’ve sought to impart upon my students is the habit of using concrete evidence in support of opinions formed or conclusions drawn.
The “why” is simple. Responsible citizens must form opinions about complex issues in order to participate fully and productively in not only their work lives but also their personal lives. Those opinions, no matter what they be, ought to be based on a thorough analysis of whatever facts are at hand on an issue.
Seems simple enough, unless there’s a fundamental misunderstanding of what a “fact” even is.