I agree with your content, but not your tone. I'd like to add that one often hears "round brackets" as an unambiguous terms for the first category. And where's love for angle brackets <chevrons>?

There are substantially more Americans than people in any other English-speaking country, and, to top it off, we're on an American forum.

It's not "stupid" to assume the dialect we're using is American English. Why the aggressiveness?

Because the cultural ignorance you are showing is annoying. There are vastly more people speaking english in the world than there are US Americans. On top of that: Most of the Americans are speaking spanish and portuguese. America != US America for one.