I don't think there's any real double standard here. Literally copying someone else's mesh or texture is not the same thing as creating a product that's similar to something else. As several people have noted, it's very common to copy trademarked and copyrighted items, and just file the serial numbers off. A plastic toy gun that looks very like a Star Trek phaser, but is sold as "Laser pistol." The K-Mart versions of Paris haute couture. Etc.

From what I've seen, making a Poser product similar to another product is acceptable, too. For example, Jepe created a body hair kit for M3 that was very similar to the one Ernyoka made. There was reason to believe that he copied her, because she had posted WIPs. He even used her promo text. While he was forced to change his advertising copy, he was not forced to change the product. Similarly, Wyrm closed his store for awhile because people were copying his magnet system and undercutting his prices. IMO, this item falls in the same category.

That said, I'd be kind of bummed if I bought it, not realizing that its inspiration was widely known. But I suppose if that's a problem, I should make my own damn clothes.