Something along #1 and #5.
I am all for displaying heritage when given the opportunity. However, this answer doesn't encompass non-tartans, and non-Scots. So then we get to #5... wearing it as a fashion statement,in and of itself? There should be more to why you want to wear a kilt than "Hey everyone look at me!!"
Just my train of thought on that one.
I even agree with the "as long as it isn't a cheap fashion store knockoff" opinion.