If i was walking down a street and a dog came up and just ran up and bit me I think it should be put to sleep. Maybe if I was doing something to provoke the dog or I was trespasing and was even "beware of dog signs" all over then it would be different.

My friend had a female husky, which are very friendly dogs, and one day it got out and went nextdoor. The people next door had tons of gerbils in their garage so the dog was playing "mom" and was putting the gerbiles in a pile. Then a little kid came in and thought that the dog was hurting the gerbils or something and started yanking on the dog's tail, yelling, screaming and all that. Of course the dog bite the kid but it was nothing serious, just a little fear bite.
This dog was very nice and none of the gerbils were even harmed but she was still put to sleep because the parents made a big deal about it and made it seem more serious than it really was.

The real problem are dogs that are being BREED to bite and attack. Any dog will bite if provoked far enough but some more than others. Some are more protective or agressive by nature while others do not have a shy bone is their body.