And those coutries aside from US is? Not to even mention that US CG don't come in constant contact with other countries ships like Chinese do all the time. Japanese don't mind them as they would simply sink those in no time if it had fired on Japanese soil or ships anyway.
There aren't that many coast guards in the world with cutters in the displacement he's talking about.
But of the nations which do, USCG, JCG, KCG cutters are all fairly sensibly armed for their different sizes.... as are the CCGs cutters.
Not sure what sinking has to do with anything, the subject is only talking about armament. I think you might be projecting a little.