The whole "banning of liquids" thing is nothing more than security theatre anyway, so the fact it's allowed on domestic flights but not international ones is moot. It's as idiotic as [some flights] not providing a real knife to eat your dinner while giving you drinks in a real glass that could easily do as much damage (probably more, based on the knives I've gotten on flights that do provide them).

Stopping people from carrying a can of Coke onboard is not going to prevent terrorists from blowing up a plane, whether they do it with the fabled "liquid explosives" or something more probable like a few pieces of C4.