With both TR an KKK items it is purely down to the motivation of those who collect them. Personally I don't have an issue with people collecting KKK items as long as they are for historical purposes only. The same as I don't mind people collecting TR stuff. As long as they are not going to incite racial or political hatred then its all good.
Similarly I am personally not in favor of hunting, however I don't have a problem with people who collect old traps etc.
It does raise some quite complex arguments. However the KKK is, like it or not, part of the history of the USA. And although I totally object to their beliefs, I believe artifacts from that organisation can be used to educate, just as SS items can.