A recent study published in the Proceedings of the National Academy of Sciences reveals that across all political and social groups in the United States, there is a strong preference against living near AR-15 rifle owners and neighbors who store guns outside of locked safes. This surprising consensus suggests that when it comes to immediate living environments, Americans’ views on gun control may be less divided than the polarized national debate suggests.
The research was conducted against a backdrop of increasing gun violence and polarization on gun policy in the United States. The United States has over 350 million civilian firearms and gun-related incidents, including accidents and mass shootings, have become a leading cause of death in the country. Despite political divides, the new study aimed to explore whether there’s common ground among Americans in their immediate living environments, focusing on neighborhood preferences related to gun ownership and storage.
It's not. You're never going to get a non-disingenuous question to this answer. You can easily get a 30 round magazine for the Mini 14, too, so the notion that the Armalite platform is somehow inherently has more "rapid fire capacity" is nonsense, too.
FWIW you can get aftermarket stocks to go on an Armalite buffer tube with adjustable combs. I've seen them. Like, in catalogs. I've never actually seen anyone install one in real life, but at least they exist. You can even get a lower for a monte carlo style "sporting" stock for an Armalite upper receiver, if you really want to.
You're ultimately correct in that it's just cosmetics.