I don't know how to help. I crossed ds with a a situation where he saw things in black and white and he didn't see the problem. It did not end well and there was never any resolution.
That said, ds knew what sexual assult and stuff like that at 10 but he inititated the conversations because he asked. He is 13 and still not allowed to was SVU I don't even think it is really appropriate for 14yr old tbh.
How is the diagnosis route for dd2 going? Any joy? Because the more I hear the more I think you should persue it.
Ds was just given rules. and we have had some very loud arguments. With black and white it needs to be be rule driven with consequences.
IF you show little zoo X then Y will happen, and Y will need to happen consistantly
If little Zoo is in the room then SVU is not on the TV/a device (make sure there is no loop holes) else you will not be allowed to watch it.
Consequences need to be preceded by a warning eg you need to turn that off else you will get banned, this is your only warning before it will happen. Then it is "you CHOSE to ignore the rule so you chose to have the ban" you didn't give the ban she chose it. You will still have many many arguments.
BUT you also need to tackle this from another direction and have a chat with little zoo about it, and make sure she understand why it is not appropriate for dd2 to be showing her. She might just grasp it and it might just help to curb dd2 a smidge.
I don't envy you zoo it is not easy to battle them when they have their minds so set. At least ds has no one to drag down to his level. I do hope you manage to get things sorted. If not just keeping talking to little zoo, i know it is sad because she is so young, but she will have to grow up at some point and it is hard to protect them completely from the world and there is so much talk of rape on the news etc when there is population displacement, the comedian who got murders in Australia etc. It is an evil world out there and with modern technology kids are more aware that it is evil and need the conversations to keep them safe and not completely scared.
Oh and one last thing. You've got this. It will be ok in the long run. Keep on keeping on.