It is perfectly possible to live in a country without learning its language. You may not need or want to have any intercourse of any form with the locals, you may work elsewhere, or in an environment where you only need your own language, and so on. I know plenty of people in this situation.
Whether or not you derive the maximum benefit and enjoyment by not speaking the language is another matter, as is whether you are showing respect to your hosts, but to say you must learn the local language is wrong.
The argument that 'you are a guest' in that country is baloney too. If someone lives in another country, pays their dues and charges, and respects the laws and environment, they are no more a guest than someone who is paying to stay in a hotel.