Not the parent, but I imagine:

1. It insults the intelligence of the viewer and indicates the rest of the show will do the same

2. Humans urinating on each other combined with torture is disgusting to the vast majority of viewers, and seeing a scene like that will naturally turn off many viewers. Even Game of Thrones saved the rape?-on-top-of-a-corpse scene for after the characters had substantial development.

On a related note, at what point does "don't judge" end? What if the opening scene depicted necrophilia? How about beastiality? There's nothing wrong with being disgusted by things 99.X% of the planet is disgusted by