The (AA/DL/UA) crew is primarily there for your safety so you best be in full cardiac arrest before you use the call button.

I can't entirely remember to be honest as it's been years - probably in passing when I tell somebody my coffee ordering experience (recounted below). This whole time since then I've either gone to the onboard bar or asked a flight attendant. Credit to the Emirates crew that keep you topped-up.

I do remember using the call button one time and asking for a coffee. I pressed the call button and a visibly annoyed flight attendant came over, who appeared to not understand (???) or probably didn't want to understand that I was trying to order a coffee... Anyway, no coffee. So I got up and went to the bar to order it - and have done ever since for all my drinks.

People order from seat also in economy (at least this was like that before pandemic). I also did it, but usually if I have chance to walk I will do it.

Especially w.r.t. coffee that's a strange story, the only explanation is that there was some misunderstanding.

Coffee, after all, is not really a 'bar drink' as the other drinks are. When you order a coffee at the bar, the attendant needs to organised to have it made in the galley, which of course is immediately behind the bar / lounge area. He / she will (in my experience) do it without batting an eyelid, but it's not what the bar is there for (I think).
The only time I was met with a frown was when I ordered an 'affogato al cafe'. It was on the menu as being available in the bar, but apparently it was a new addition and had obviously not been ordered before (at least not to this crew). I pointed out that it was not my personal whim, but that it was on the menu. A slight panic ensued but 10 minutes or so we were presented with two really nice affogatos, and a thank you for pointing this new menu item out to them.

Definitely sounds like a random incident and as someone else mentioned- very odd for a coffee request which is not even prepared at the bar. The bar is optional for ordering and I think most people order from their seat and that is the general expectation.

Wow, really interesting stuff, thanks all!
I'm really glad I mentioned all this!
Really looking forward to my flight this weekend :)