My Chizzie gets the same remarks. She is big boned, very muscular and is sporting a nice thick layer of FAT. So at 9 lbs. she is the brunt of the big jokes -- for kicks, I take her and her Peppy (who is 3 1/2 lbs.) out together. So I get both the BIG comments and the little comments.
I have come to realize that a lot of people are envious of us for owning Yorkies. There are so many wannabees out there that simply can't afford them. It is like a thoroughbred horse person seeing someone who has a Kentucky Derby winner.
Jealousy in some cases, an in other cases people just wanting to communicate with "a person who owns a Yorkie". In their effors to sound intelligent, they show their ignorance.
I have learned it is best to smile, and say would you like to pet them?