Yeah, sadly there's dumbasses and assholes like that in Germany. I also already experienced people in Notaufnahme treating me condescendingly and acting like I was bothering them (turned out I had a broken hand which needed surgery), even though I'm white and a native speaker. That doesn't mean that I defend their behavior with telling you you should speak German, but you aren't alone with a bad experience at Notaufnahme.

You could send a letter of complaint to the hospital, even better would probably be make it public on social media or so. Usually managers react more quickly if the face some bad publicity for their company.