Mac, two points that you address: the fact that standing behind someone wearing a horizontal shoulder holster with an open muzzle causes one to be staring at the muzzle of a pistol, and the fact that a drawn weapon sweeps everything that it is pointed towards.
Point one - you seem to be saying that a safely holstered pistol oriented towards your head is more "disrespectful" than a safely holstered pistol which is pointed towards your leg. I do not see how respect enters into the equation any more than safety does. Sorry. There are those who say that carrying a weapon at all is disrespectful because it upsets certain people. I would assume that your definition of "disrespectful" is not the same as theirs.
Point two - when a weapon is drawn from its holster, it sweeps everything in its path, regardless of its original orientation when it was holstered, and it continues to do so until it is safely reholstered. This is an unavoidable fact that applies to shoulder holsters, belt holsters, belly bands, ankle holsters, "Thunderwear," fanny packs, purses, day planners, and anything else that you can think of. You may argue that a weapon drawn from a belt holster sweeps fewer objects, but that is not the same as saying that a weapon drawn from a horizontal shoulder holster sweeps objects and a weapon drawn from a belt holster does not. Again, sorry.
Respect and safety, two issues that we should be much more cognizant of than the average citizen.