In the past quarter, TSA intercepted an average of 16.8 firearms per day, 93% of which were loaded. I'm quite happy with that many less guns on my flights (imagine what it would be like if there was no check - this is just from people who forgot that carrying onboard is not allowed).
People forgetting they are carrying a loaded firearm into an airport feels like a pretty US specific problem, and there are ways to screen for guns without the massive inconvenience that is TSA. Other parts of the world still have security checks at airports, just a lot more efficient.