At the start of every class I teach, I make a standard disclaimer that although I work full-time for a LE agency, my HCP course is on behalf of my private company, and any editorial comments I may make (and I'll make plenty) are my views only, and do not necessarily reflect the policy or sentiments of my LE employer.
If this guy was instructing the class under the aegis of the Police Department, then I'd agree he went overboard with his soapbox opinions, and you're probably right that a class full of new, uninformed shooters might value his opinion as gospel. In that case, a courteous, well written letter of concern might be in order. (I know there are two sides to every story, but I am taking your version at face value).
As for this, I see a fair amount of both criminals and crap in my real job, and I support more criminal control, not more gun control.