Why don't all members of the Air Force have to be fully qualified to be a rifleman in case of hostile events?

Since I was in both the USMC and in the USAF, I believe I have picked up some insight into this issue through the years I was in.
Yes, in the USMC – everyone is primarily a ‘rifleman’ and then then they have their MOS. So when Sh*t hits the fan – everyone is capable of being part of the defensive and/or offensive situation that is occurring.
In the USAF, the Security Forces (as labeled currently) are the army for the Air Force. Their primary mission is protection of Aircraft, Equipment and Personnel. There are other AFSC’s that need to provide armed protection (One example: CE); but for the most part CONUS units do not require personnel to ‘qualify’ unless they are deploying OCONUS – they might ‘FAM’ fire every three years possibly if their lucky.
My unit had a FAT’s system (Computerized video projection system where you could fire on range targets, or you could create ‘tactical’ field scenarios, or utilize ‘shoot don’t shoot’ scenarios). This system utilized wireless weapons (M9, M4, M16, M60, M240, M249, M870, etc.), they created the sounds and kick back like a normal weapon and even the weight was really close – magazines were utilized as well for reloading situations. This eliminated the need to fire ‘live’ ammo for the rest of the base unless they were deploying (then they would ‘qualify’ with real ammo) but at least they were getting proper instruction via our CATM instructors and ‘trigger’ time.
Not sure why this is not a widespread utilization among the branches – saves a lot of time and resources, while providing proper training situations and environments that you can’t normally take advantage of. We even had civilian law enforcement agencies come to the base to use it.
Unless you learn from history you will, keep repeating bad situations.
Vietnam showed the need why everyone should be properly trained with a weapon. Back then airbases were protected by the US Army, and the USAF only had air Police with .38’s roaming around inside the base. When the army would get called off – the bases would be overrun easily since the AP’s were not trained (at the time) and the base populous wasn’t either.
Flash forward to another situation with the US Army and convoys – personnel weren’t properly trained on weapon jamming fixes and people died or were captured.
Even up to today, in the military unless you are in a field that takes you to the ‘hostile’ environment you don’t get the proper weapons training that could save your life or the lives of others if the situation arose. It has happened at various CONUS bases in the recent past where some individual or individuals have opened fire in occupied buildings wounding and/or killing people.

We get that training before deployment...regardless of the weather...Torrential rain for instance.

You must be at a low deployment base. My guys qualify pretty much every year between the two deployment band we have folks going out and folks coming back with no lull. If you are assigned to a band and aren't broke, your deploying.

This is why you have have Army aviation to protect the Air Force guys on the flight lines in war zones ;)

Altho I do know what the basic tng for the Air Force is like I would say that this should have been taught in basic tng.

Actually, my superintendent (prior Soldier and prior Marine) and I were discussing this recently. If they need an "all hands on deck" (especially with the branches cutting everything/one), the USAF is in trouble. The Marines and Army go through combat training, formations, firing squads, etc. The Air Force? Unless we are Special Operations or Security Forces, we get one day to learn how to shoot, actually shoot and then qualify. I have only touched an M16 twice in my 5 years of being in. Once in basic training, and once when a rifle was needed for JRTC.

IMHO the issue is the word "all". If you are in billet that has the potential to deploy downrange, then you need to be qualfied on a weapon (at least M16 or M9). However, not everyone in the USAF is goint to deploy. Heck, with global reach of aircraft, most USAF Airmen can do their wartime job from bases in the US or in allied countries. Most will never go downrange into a combat zone. It is a waste of money to qualify airmen with live ammo who will never be put into a position to pull the trigger. The same can be said for many Navy and even some Army billets (like the one I currently am slotted to). Now I DO believe, with modern simulation tech, that those in non-deploying slots should do regular weapons familiarization on simulators (ie weaponeer) so that they at least are familiar with the weapon.

That was the hardest thing to get used to when I transferred over to the air guard from army guard.
Because if afsc I only qualifies every three years unless I was deployed

At least the rounds are pointed in the right direction.

I was in the security forces for 16 years and what I know is many people have no need to be anywhere near a weapon. Not even a fork.