Earlier quoted context omitted.
Can you please describe the situation? Are you saying someone asked a question in English and got a reply in German? Or are you saying there was an office with 20 German-speaking employees and one English speaking one and then much of the informal talk was in German? It‘s true, it‘s like that. And that‘s not xenophobic. It may be impolite, depending on the situation. It‘s not specific to Germany as anyone working in…
Simplest example: my first time in Munich I was struggling with the subway instructions, they were all in German and this was before Internet on smartphones and Google translate, so at the entrance of the station I asked several people in English if they speak English and can tell me what ticket to purchase (the different ticket by area concept was completely foreign to me). A couple said yes, I asked the question "w…
Aside of that: it is rude and I polite but not xenophobic. They can rightfully expect that you speak the language of the country you are in.