@hightor,
Thank you, hightor!
I took your words as the following:
"Going Dutch/American/Republican" can sometimes be neutral, without any intention of criticism, because the words Dutch/American/Republican in themselves do not have any negative meanings.
I hope I'm not going on the wrong track.
On the other hand, I think we can say that "going mad/crazy/insane" always, or often at least, refers to something very negative, because the words mad/crazy/insane are just negative.
Both of the expressions are "go + adjective," but the former can be either
negative or not negative, while the latter goes almost always negative. This may be due to the fact that the types of adjectives employed in both sentences differ, though I'm not so sure. Help me, linguists!
Anyway, thanks a lot!