If I purchase goods from a company I should be able to sell them to anyone I'd like, certainly the goods should not be wasted, so that a manufacturer can expand sales, while already produced goods sit unsold. There is no reason to ban grey market goods, but for the protection of the wealthy and they don't need protection. Retailers should be allowed to sell grey market goods.
Grey imports refers to the secret but not illegal sale of goods at a high price but if there is a demand for products or services it should not matter what the origin of the product or the price is. Markets are self adjusting and if the public buys it then it's okay. When the public stops buying standards will change.