It’s not even a colloquialism, it’s perfectly correct grammar. Get is a synonym for receive, and whilst “can I receive a coffee” is an insanely formal construction that only a robot or alien would use, “can I get a coffee” is totally legit.
The reason to hate it is because it sounds American and everyone hates Americans.
I've heard people argue that you should say "Can I have a coffee?", which is obviously nonsense because, of course, anyone can have/own/hold a coffee. The question is can you obtain one.
It’s not even a colloquialism, it’s perfectly correct grammar. Get is a synonym for receive, and whilst “can I receive a coffee” is an insanely formal construction that only a robot or alien would use, “can I get a coffee” is totally legit.
The reason to hate it is because it sounds American and everyone hates Americans.