WHITE PLAINS — A display of Nazi paraphernalia at this weekend’s Westchester County Center gun show drew swift condemnation, as the county, in response, said it would review its policies.”It is an unbelievable insult,” said Richard Laster, chairman of the Holocaust and Human Rights Education Center in Purchase. “I will certainly try to reach (County Executive Rob Astorino) and make him aware of this and certainly, in the future, avoid a repeat of that situation.”The selling of Nazi memorabilia and other controversial artifacts at military history shows is common and legal. Despite that, many of the items in question would be banned from online auction sites, such as eBay, due to their controversial nature.