Hey Trevor, the way I see it, the fact that you can kill somebody with a 1/2" blade doesn't invalidate the efficacy of, say, a 3" blade limit as is common in some high crime cities in exactly the same way that the fact that you can kill a person with a car at 15mph doesn't invalidate the efficacy of a 35mph speed limit is common in some residential neighborhoods.
The point of a 35mph isn't to stop all car related deaths. The point is to minimize the overall number of deaths and to give cops something to charge people with when they act up and speed dangerously. In a city like Boston which is near me, they have problems with drunken college students getting into brawls and with gang violence and their 3" blade limit is designed to minimize the number of knife related deaths and injuries (not eliminate them) and to give cops somethings to use to arrest guys who are posing a threat.
This is sensible to me, just as a 35mph is. Note, I break both laws regularly but I don't in trouble with the law and I use a lot of discretion.
I think that most people would see a 6" Buck 119 as a more dangerous weapon in the hands of your run of the mill drunk and disorderly type or your average street thug than, say, a 3" Buck 113. I'll reckon there are some martial arts types who would prefer a 3" blade, but that's not what the laws are about. The laws are about the average case, and the average thugs and bar fights.
Trevor, 99% of this thread is about using judgement in context. If I were out walking my dog in the early evening and encountered you carrying one of those big D-cell Maglite and if you were between the ages of 15 and 35, I would just immediately assume you were up to no good. The same would be true if you were carting a 10" screwdriver, a baseball bat, axe or climbing axe.
True story... In college, a buddy and climbing partner of mine rode the subway to a climbing store to buy a climbing axe and when he returned, he said, "It's a lot easier to get a seat on the subway when you're carrying an ice axe."
Things out of context make people nervous and for good reason. Knives used indiscriminately and without justification make people nervous and for good reason, IMO.