I would be pretty upset. I'm short (around 5 foot) so I am always hearing comments about my height such as "So just how tall ARE you" and I think it is sooo rude --- I don't go around asking people their weight... I mean you can see how tall I am. I think it is a lot like that for Yorkies. I'm sure I won't mind the ones saying oh he is so cute and so tiny! But the ones acting like they aren't as good of a dog, I won't be too happy with
As far as the clothes thing, I guess everyone is allowed to have their own thoughts, but unless it is asked for (such as having a convo about it) a simple comment is more than enough to let you know what they think - and that is if you are kind

They wouldn't like it if we said something like OH MY! You don't even have a coat on that big dog, it is freezing outside, what a bad owner... (not that I think that!).