It's hilarious.
Yes, it is bad behavior. However, I have yet to see a poorly behaved small dog inflict great harm on someone. Most large dogs do more damage if they jump on somebody than a tiny one does if it bites. Have you ever heard of a healthy adult being seriously injured by a Chi?
Please do not waste your time trying to convince me that little dogs are dangerous. I have owned two small dogs with short tempers and have been bitten by them quite a few times, and the worst that's ever happened was a "OW!" and a bit of blood. No hospital visit, no stitches, just a band-aid. I will admit that a small dog, with a huge effort, could seriously injure a baby/small child or fragile senior citizen, but they honestly pose no threat to most people.
My Papillon is extremely quick to bite. It isn't his fault, he isn't a "bad dog" but he is very easily "set off" and tends to stand and fight when confronted, rather than shy away. I have lost count of the number of times he's gone after me. Why is he still alive? Because no matter how hard he tries, he can't hurt me or anyone else. THAT is why small dogs are not held to the same standards that large dogs are.
This rant isn't directed at anyone in particular, I just get tired of people saying that "small dogs and large dogs are the same" when they quite obviously are not. I have owned and loved both, but if you neglect to train your Chihuahua, chances are nothing bad will happen to you or someone else as a result. If you neglect to train your Mastiff, somebody very well may wind up dead. I personally believe that dogs should be trained and treated properly regardless of their size, but it is obvious why small breeds can get away with aggression and large breeds cannot. I wouldn't dream of letting a Fila do the things my Papillon does.