I get that you're trolling here, but let me break it down very simply for you - because you've had this issue before when you and I went back and forth on gun laws. You seem to want to get into it again, so sure. Why not.
The whole argument of "good guy with a gun stops bad guy with a gun" is the solution in a world where gun control doesn't work - and here's the punch line - because there are already 100's of millions of guns in the wild. That's it. So the best solution is that an armed populace is a safe(r) populace.
Obviously, and no rational person would argue against this, a population with absolutely ZERO guns would be the safest way for things. And no, I'm not one of those "gotta have guns to protect you against the government" guys. The problem remains - and you gun control folks have never been able to solve this - that you can't get the illegal firearms off the street. You've got ZERO ways to do this. Zilch. Nada. So instead you want to go after the firearms I'm going to use to protect myself from the bad guys, like that's a solution I can live with.
The reason gun control works in places like airports or political conventions is because you can clear the area of firearms, and control access to firearms completely and unerringly to the event/location. So it works. Again, and I've already said this to you, if you could somehow magically ask everyone to step outside the US for a moment, and then remove all the firearms in the US, and then control everyone coming back in, you could create this safe environment.
But you can't.
So that's why politicians choose no gun events - because they can, and its the safest. But you can't do that with schools (or rather, you can if you treat them like airports) or the mall, or the movie theatre, or the grocery store, or night clubs, or fast food joints, etc.
If it still isn't clear, I'm not sure I can help.