Nice strawman argument there. No one here is proposing changes to school or aviation security rules.
Merchant vessels typically used to carry a variety of artillery and small arms for defense against pirates and hostile navies. That practice largely ended when the UK and then the USA established global hegemony and secured the sea lines of communication for everyone. But now the USA is no longer willing or able to play that role, so either merchant vessels have to be able to defend themselves using deadly force again or else trade will largely cease along routes within range of shithole countries.
You are perhaps mistaken here. The FAA allows passengers to take guns on planes provided they are documented and secured and checked into the hold. What the FAA is concerned about is people being personally armed on planes and there are obvious reasons for that.
They are largely unrelated to the reasons countries might have for being nervous about merchant vessels packing anti aircraft weaponry.
You are I think getting lost in your analogy and in the process conflating two different things:
- the reasons countries might want to prevent people from entering with weapons
Vs
- the reasons countries might have for being nervous about armed merchant vessels in their navigational waters
Why do you think schools ban kids to carry weapons ?
Do you think letting anyone to bring weapons into any country might end well ?