And your agreement for someone else to play a bass "left handed" is somehow required because....?
If you don't understand the intensity, why not live and let live?
EDIT: For the record, I am also a lefty who plays "traditional" as you say (and as you can only say on DB not electric). My son is also a lefty and plays lefty (he's a guitarist and doesn't play DB, although he can passably play it "traditionally"). While I generally agree that there are advantages to playing DB "traditionally" (and more importantly, in "traditional" situations you HAVE to), I can see from watching my son evolve as a musician that there are definite benefits to imputing handedness to DB, and playing it the other way around. I don't see why it is anyone's business how someone chooses to play an instrument. If I showed up at a bluegrass or jazz gig with my bass strung the other way around and played some killer bass - would anyone give a rat's a$$ what direction I was facing? No. And they shouldn't. So why do people jump in with the philosophical judgment every time someone asks such a simple, mechanical question?