I think there needs to be a balance. She gets snippy with these people because ALL they do is put clothes on their dog and parade it around like an accessory and put absolutely NO thought into what the dog needs in terms of training, WALKING (Yes..small dogs have legs, they can WALK), and any mental stimulation at all. I really am amazed at the way some people on those shows just have NO clue that a dog can actually LEARN something. Its so odd.
That being said I feel that if you HAVE given your dog what it needs, it knows how to behave and isn't a brat, gets walked and can use its brain, putting a shirt or coat on it when its cold or for a party shouldn't ruin all of that and is totally fine. She did say in one of my favorite episodes of the British version (the episode with the rescued chinese crested) that she's fine with them wearing coats in the cold. Paddy's definitely got a few jackets and he's gonna wear them no matter what any trainer would say and Paddy's weren't fond of clothes either.
That episode actually has my favorite quote of hers. She says "if that dog was a human, it would either be in jail, or in a mental institution!" ..cracks me up. I sometimes really wish I could be that direct with my patients.
Lastly, since this is longer than I intended. You can't always win with other peoples opinions. One time i went out with my dog in a sweater and someone said I shouldn't dress him its bad, and literally a day later I walked him up the street quickly and it was chilly but not cold and someone yelled at me that my dog must be freezing without a sweater.