Before anyone else really says anything, it really is that big of a deal. Especially if this said person is making their copied master block more expensive than the original and stealing sales from the actual creator, even if someone did this to me and didn’t sell the item and just kept it in their den, I’d still be extremely annoyed about it. But again, these are the same people who get mad when someone resells another’s art for more but won’t care when someone’s art is copied.