No, they don't look at us all the same. Many Koreans today are a lot more sophisticated than that, especially if they have lived abroad, but it can take a long time to change someone's mind here.
Believe it or not, you can find (much more polite) ways to rebut Koreans who are rude or speak impolitely to you etc, but you have to do so in a way they understand and are willing to accept or tolerate--Korean. And once you have done so, it is a good idea to follow the social norms and either drop it, or pay the price for escalating such incidents.