The Rifle as Phallic Symbol
You may be too young to remember, but in the 60s certain cars were considered phallic symbols, for men short on other attributes. They produced 1000’s of gag lines in film.
These semi-auto rifles that look like he-man weapons came from the same wannabe he-men of the 90s. And those he-men generally arose from the video game culture beginning in the 90s and generally agreed to have been a major cause of the Columbine shooting in ’97.