In your head only.
If they're subject to regulation, why aren't they regulated already?
Assault weapons can be regulated. You just can't process and accept what weapon falls under category of "assault weapon" or not.
US Army and Defense Department definitions of "assault rifle":
"Select fire" means it is capable of fully automatic or burst fire as well as semi-auto. "Semi-auto" means when the trigger is pulled the rifle will fire once, "full-auto" means that when the trigger is pulled the gun will fire until it runs out of ammo or the trigger is released.
Assault weapon uses an intermediate round that is accurate at least 300 meters away so more accurate than a submachine gun but less accurate than a hunting rifle.
The definition of assault rifle is clear and has only one meaning, despite of politicians trying to change the meaning to fit their narrative, where "every scary looking gun is an assault weapon". People who know nothing about weapons, such as yourself, and people who know very little or nothing about constitutional rights, such as yourself, are falling for that narrative. The rest of us are "not buying".
According to leftist proposed assault weapons bans the rifle on top would be legal while the rifle on the bottom would be an illegal assault weapon. In reality, they are the same model of rifle with the same firing spec, just looking different.
When the constitution mentions arms, they didn't differentiate between one type of arms or another. I'm pretty sure terms like select fire or assault weapon weren't even considered. Therefore, I'm having a hard time understanding why you have such a problem with the constitutionality of regulating ALL arms. We can discuss whether all arms should be regulated in the same way if you would like, but it's clear that it is constitutionally acceptable to regulate them all in exactly the same way.
The same Constitution that you're calling on is securing our "unalienable rights".
To simplify it just for you, you have no right to kill someone, but you can defend yourself from being killed.
The 2nd Amendment is giving protecting your right to defend your life.
Every weapon can be used to attack or to defend. Therefore, every weapon can be called "assault weapon". If I use banana to choke you, that was "assault weapon". Left want's to label every weapon as "assault weapon", and without 2nd Amendment they would probably succeed. If semi-auto weapons are banned, what's next? Call hunting rifle a sniper, and simply ban it because it's weapon of war.
As I mentioned above, automatic weapons are considered assault weapons. Semi autos are not.
Although I don't agree with a statement that "you don't need machine gun to defend your home", and I think ban on automatic guns is unconstitutional, because state can still have them, I can accept not having one to defend my home.
And last, when the Constitution mentions freedom of press, they didn't differentiate between one type of news papers from another. I'm pretty sure terms like select cable TV, internet, or Twitter weren't even considered. However, freedom of press is constitutional right regardless of technical advancements we have today.