Replace normal with common, and my original comment stands. In many cultures people often casually say "how is it going?" when they don't mean it literally and they are just expecting a token "good, you?" in response. Some people might view it as unnecessary and insincere, but they don't generally go around lecturing others and telling them not to do it. When you're faced with a harmless cultural behaviour like this, the polite thing to do is just accept it and move on with your life.