Your arguments against armed populace to deter tyranny are in fact arguments for it.
1) In a world where weapons arent infringed then any weapon the govt is allowed on american soil and used against the populace then the populace is also allowed to buy. Ergo by default there is no asymetry.
Moreover even if we accepted the current state of affairs where the govt is allowed more power, the fact that the other side is better armed is **not** an argument for your side to dearm itself.. If anything its an argument to ensure you keep as much armament as you legally can muster as disarming only serves to make the asymetry worse, not better.
2) Using an armed populace as a fear tactic only works when people are used to be around armed people and thus associated it with fear. By arming the populace and encouraging people to carry their guns it exposes people to it and makes the fear angle less likely to be exploited.