I'm not easily offended or turned off by violence if there is a purpose to it

Same here. I've got a pretty high threshold for movie violence and I'm still surprised at how much I reacted to this when I think about it. I think it's how much of it was sexualised violence, more than just the violence itself. In the UK you cannot depict sexualised violence, so in a way I've been quite sheltered from that kind of viewing, despite having seen plenty of torture porn, actual porn, and general violence. So those images really embedded themselves into my consciousness, more than maybe straight ultra-violence would have.