Your visit to the Korean DMZ somewhat reminds me of how many Japanese tourists I saw taking pictures at Pearl Harbor. People are fascinated by sites that represent history. I had a picture of myself taken in front of the Berlin wall before it was torn down. As someone of German descent, what was that... American German privilege? When Brits run around Waterloo having pictures of themselves taken there, are they offending the French, who lost. Is that ethnic privilege?
What if my African American grandchildren do what you did, would that be African American privilege. It seems more like you were just being an insensitive "tourist" and last I looked they come in all skin colors.
Try to make things less about race... because they really are not about race in most instances.