I don't think it is real rare. One sold on this site for $395.00. It was listed as a boat flag. It would have flown on a German ship. Why don't you show the whole flag? Anyone that does a search for it will know what it is.
It's historic and war related. No need to be politically correct. If someone is offended, I think there might be a "safe space" on a college campus somewhere they can hide.