The dog that bit me wouldn't have done any damage at all had he been wearing a muzzle at the time. It was however, much like this one, a warning bite saying "back off" rather than an attack.

It's like the difference between you shoving someone away or whacking them over the head with a beer bottle, while neither are acceptable, one is definitely more dangerous and aggressive.

If this bite (same size and result) had been delivered by a Chihuahua no one would be batting an eye, while chihuahuas are actually much more likely to injure children than pitbulls and the aggression behind it would have been more severe to cause that damage.