So where do we go from here? How do we prevent this from happening again? It seems that there are two schools of thought (generalizing obviously): 1. Disarm everyone, and 2. Allow everyone to carry weapons. Regardless of which side you fall in, neither work perfectly unless they are complete (i.e. all weapons are gone thus criminals don't even have access, or everyone is armed and no one has the upper hand). The problem with both absolutes, is a deranged person will always find a means to carry out their ill will, whether that's a gun/knife/driving a car into a crowd.
The safest computer is encased in concrete, and buried 6 feet underground. Much in the same way, the safest society would have each of us locked in a room, with no interaction. What we have to figure out is this: How much liberty do we all give up, to limit the devastation of the senseless acts of a few?
Nice strawmen. There are obviously options in the middle, namely, increasing traceability of weapons and ammo and shutting down channels that where weapons are allowed to change hands anonymously.
The proliferation of weapons is one thing, but the fact that these tragedies occur and we don't have a way to follow the chain back to the disreputable dealer who sold these armaments - and shut them down - is just non-sensical.
The 2nd amendment fundamentalists who don't even want question how these weapons can get in the wrong hands - often use that same strawman you pose above - which is rediculous - many folks support the 2nd amendment yet find the need for further action to prevent these events from happening.