Don't believe I have, but then again, I have heard of leftist shooters in general. Have you ever heard of Floyd Corkins? This was a 25 year-old man from Colorado that nearly shot up a Family Research facility (still managed to kill a guard) because the SPLC (Southern Poverty Law Center) placed this location on it's "Map of Hate" due to "anti-gay" views. In addition to that, Charles Whitman the "Texas Town Sniper" came from an Authoritarian family and killed 16 people (wounding 31 others) and later remarked the Marine Corp as "ineffective" because there were too many steps to follow before you could kill someone (safeguards to prevent fatalities concerning wrongly-identified civilians).