I first became interested in kilts when I learned that my lineage can be traced to the highlands of Scotland. My interest has continued because I enjoy wearing the kilt and find it to be comfortable and practical. I also enjoy learning about history, tartans, and clan lore. It is all a sort of a hobby for me, and I have no intent to insult anyone's sensitivity regarding their own heritage or birthplace.
U.S. (and Canadian) history is very short as compared to most nations, and I think that it is only natural for us to pay homage to our Scottish heritage and celebrate it as part of what makes us who we are.
After all, the U.S. economic system was based largely on the thinking of Adam Smith, the Scotsman who penned 'The Wealth of Nations'. Western philosophy and government is also largely influenced by Scottish thinkers such as David Hume. I see my country as having resulted from the ideas of our Scottish and other European ancestors, and my interest in their traditions is a celebration of them, not an insult.
Blue jeans originated in the U.S. and are now worn around the world. To me, that only means that lots of folks from lots of places like blue jeans, just as I like kilts.
Cheers to all my fellow kilt-wearers of any heritage!!