I don't think anyone is entertaining such comments, unless they see an opportunity for meaningful discussion with the commenter. As for caring, well, it's tough to put up with the same types of comments about your dog/the way you train/the way you raise/care for/etc, from those ufamiliar with the breed or responsible dog ownership in general, without eventually getting irritated.
I haven't gotten too many unusual comments about Olive, lately it's been sideways glances at the Thundershirt when we're at stores (it's almost like a scarlet letter, it seems). There is a woman we run into occasionally on our walks who has told me that Olive is not, in fact, a Sheltie, because they "don't come in that color". I explained that Olive is purebred, with a highly respectable pedigree, but this woman said I was suckered.

Oh well... my dog's smarter than her anyway!
People who make comments like those mentioned in this thread are not doing the breed any favors, and I think that is a large part of the reason we are quick to be annoyed by those comments.