I think there is a very good reason for a dog to have a full tail, which is that it is part of how he communicates with the rest of the world. I have wished many times that Thor's tail is longer so I can get a better idea of how he's feeling. I think even more so for other dogs.
I don't think that people who like the look are cruel and terrible people, I just think it has no benefits beyond aesthetics, and why cause the dog any pain if you don't have to? I prefer the look of circumcised males, but I know that's because that's what I'm used to. In Africa, it is being recommended because circumsion reduces the risk of spreading HIV. Either way, I don't have strong opinions on it, though I probably would circumcize my son, or leave the decision up to my husband.
There are many other bigger issues out there, but hey, this is a board about yorkies!
And to end with one inflammatory thought... for those of you who like docked tails, how many think that dyeing your dog's hair, which has NO negative after-effects, is cruel?
I just mean to say that we have a lot of different opinions on all kinds of "body mods", and maybe they aren't always consistent. When did inconsistency ever stop someone from having an opinion?