Does each language have "lefty loosey righty tighty"?
The world has a lot of different standards for a lot of things, but I have never heard of a place with the default screw thread direction being opposite.
It's also torches and everything after the regulator, which run at much lower pressure. At least in NZ
I think it might be because they're connected and disconnected regularly so misconnection is a common problem, even with colour coding. Gas work on houses involves actually putting the fittings on pipe and is done by people who should be concentrating more on that rather than on what they're about to weld/cut.
Please tell Tongshen, who manufactures the popular TSDZ2 motor. The pedal keeps coming loose because they don't do this. I keep a key on me to tighten it when it starts to loosen.