Shouldn't I have the right to walk outside without being terrorized by a potentially-lethal pet?  Are we living in a civilization or not?  

People usually get dogs for companionship, hunting, or protection, and the desire for protection often causes people to get very large and dangerous dogs.  
An owner's desire to assuage their fears by having a lethal dog does NOT supersede a citizen's right to not be terrorized.  I believe the opposite is actually true.