So
Quincy-san and
Idiot-san tried to tell you the annual 411, did they? Oh look, it's a horse I can beat to death to procrastinate for another thirty minutes. ♥
The truth is that shinigami are none of your damn business, and you should try to ignore them at all costs. They shouldn't even have to be acknowledged to you in your daily lives. They're like fungus or something, they appear where dead organic matter is and move stuff along.
And without being too moralizing or us-and-them about things, the Quincy did the same thing, except they just stamped out what was nasty instead of sending it away for recycling until it got better. It's a pretty good effort, considering the fact that they were never working with the full rulebook to begin with, if you get my picture.
Either way, it's just more bureaucracy, and you can't fight city hall. Well, you can't win anyway.
But you can irritate the crap out of them from far away easily enough.
The arrancar are even
more none of your business, except that you should stay away because they're heartless sociopaths and they still owe me for damage to private property.
The same goes for the vizards. It's pretty much all
none of anyone's business.