As I think the part that it is a female body adds to the controversy (lol, it's the only important part of a woman's body, hahaha, right guys hahahaha, so funny, so incredibly, funny funny funny funny), I think the controversy is mostly focused on the fact it is a mutilated torso.
Male or female, zombie or not, it's a mutilated torso of a human. That's pretty morbid to a lot of people. There are a lot of fans who loved the first one, who want to get a special edition, and do not want to have a mutilated torso on their shelf with all their other collectables. I know some people that would love this, but they collect shit like this and that's their business.
For this collectors edition, I think they could have gotten away with a full body zombie 7in statue, still female and mocking how people pose female statues. Have a boob missing or something. This thing is just tits and ultragore. It's disgustingly juvenile.