I'm not sure that I agree. Prior to metal detectors and airport security here in the US plenty of guns were carried on planes and very few bad outcomes were the result. I've heard of planes getting hijacked and going to Cuba but nothing in the way of mass murders on airplanes.
I wish that instead of just stating this as a fact that you had argued it in some way. For point 1 you gave reasoning. For point 2 you just said "this is true" and stopped.
If you had said something like "air is necessary for life" yeah sure, I won't belabor that point. It's scientifically verifiable at least for humans.
But when the parent was posting "I wish people could just carry rifles and it not be a big deal" it's clear that your position is more of an opinion than a fact. You might consider it a fact, but you're replying to glenra who quite obviously doesn't agree.