One of my coworkers immigrated to the US from a Spanish-speaking country. His college studies had been French and English literature and he is fluent in both languages. Coworker was riding on a street car in his native country when two English-speaking g*a*y men began to make very sexual comments about him--his body, what they might like to do with him, etc. He let it go on just long enough, then blandly turned to them and said something like "Oh, you really think that about me?" They were a bit embarrassed, but then continued the conversation--in French. This time, when Coworker spoke up, the men couldn't bail out of the streetcar fast enough.
I have traveled in something like 40 countries. I do not know the languages of a lot of those countries, but I have always made a point of learning "hello", "please", "thank you" and the all-important "where is the toilet?" I once figured out that I could say either "hello" or "good morning" in something like 25 languages.
But, in defense of non-learners, learning a new language, even a few words of it, is very difficult for some people. Others might be able to learn a few words, but never can get the pronunciation right. I remember trying to teach an English-speaker how to say "thanks" in Turkish (tesekküler) . He simply could not pronounce it correctly. The correct pronunciation is something like "tesh-e-kew-lair" He kept saying "te-SHEKK-ler." Even when I spoke both versions for him, he genuinely did not hear the difference. He especially did not hear the difference between "ler" (rhymes with the American pronunciation of "her," the R must be pronounced) and "lair" (rhymes with "hair"). He admitted to being a strong visual learner and said that he had always had problems with language.
[Yes, I do know the correct pronunciation of tesekküler is a little different. But it is hard for most speakers of other languages and I was just trying to help him say something intelligible. We finally settled for the informal "sowl." Not always appropriate, but much easier to say and the kind Turks will appreciate that you are trying. ]