explain this to me

i can't bring on more than a quart sized baggie of 3 oz sized containers on a plane.
i can't bring my tiny swiss army knife on a plane.
i can't take sharp pointed scissors on a plane.
all for my own safety, right?

then why are glass bottles allowed? won't broken glass cut like a knife?

i really wonder what guy in his ivory tower is making all of these rules. does he secretly work for glad or ziploc and needed to boost quart sized baggies?