Until the last two decades or so, the vast majority of hunting rifles were bolt action and not semi automatic. In fact, bolt action rifles are still generally the more accurate rifles.
Very few people (at least ones worth bringing into an adult discussion) think we should ban or further limit bolt action rifles. Hunting is okay. There is almost zero need for a semi automatic rifle when hunting. Most hunters even agree that bolt action rifles are generally better overall for hunting due to it being more accurate as well as cheaper to use (can much easily load your own ammo for bolt rifles than semi due to more tolerance in minute differences in loads).
The arguments on why we need Semi automatic rifles in the hands of civilians don't really convince me.
One argument is self defense. A shotgun or handgun is better for self defense in almost all cases.
The other one I hear is that they're fun to shoot. I'm sure they are. Rocket launchers should be fun too. I bet RPG's are a blast (heh) to fire. Doesn't make that a legal basis for owning the rifles. (Though making them legal to shoot at approved fire ranges might be an option like some countries do).
What argument am I missing?