What worries me is not the fashion statement . . . its what they are doing with the dog when it is not a fashion statement. Dogs have been fashion statements for a long time . . . purse dogs are just the newest variant. My dog is a fashion statement in a sense, though I didn't get her as part of a fad. But having her with me, and her looking the way she does, is a fashion statement . . . and expression on my part. I'm not sure how one avoids that!
And I will have to say, I suspect those itty-bitty dogs are safer in someone's purse than they would be just being walked on a leash through public places. I saw a little Pomeranian on a leash have a total breakdown at Home Depot . . . it SHOULD have been in a purse, or in the cart, or something. I think its fine to have purse dogs . . . if they have any idea how to care for their accessory and bought it responsibly. Of course, I suspect most of them didn't . . .