The star certainly is a part of history. But the pain and suffering that is beneath that star is something that cannot be turned into money and passed on to another collector.
I do not judge them who want or have one of these in their collection, it is a historical item, and some people collect this kind of items.
And I do not judge the sale of these stars, as long as one does not sell them with their only reason to gain lots of money, that I would see as gaining profit from the suffering of others. But if someone has to sell the item, be it because a person in the same household feels uncomfortable with the star in the house or they are themselves not comfortable around it, then I see nothing wrong in it, as long as they dont demand very high prices.
Or they could hand it over to a museum, where it would be handled with care and respect, and where future generations can come and learn about the pain and suffering that fell upon those who were forced to wear this star.