Ok. Thanks for all the responses. I think we covered a lot of opinions and established the facts about current controls. This is my final statement and I leave it up to Game moderators if they want to pick up this issue or not. Since it hasn't been a widespread problem, it may not be worth dealing with.
1. I raised this because I've been playing BM for many years and I haven't been disturbed by previous posts, so I am no snowflake. This one did disturb me, I felt it was straying into unnecessary explicit brutality and maybe rape fantasy. I appreciate opinion is divided on that.
2. Currently the only restrictions are vulgar language and not Roleplaying other peoples characters. Neither of those restrictions apply here.
3. Here is a possible way to deal with it if you think its a problem. You could have a mechanism like the vulgarity rule where other players decided if a post contained excessive violence or sexual content.
4. Or continue to go on as we are. We have managed without any control so far. I guess that if any post was so excessive as to cause a massive amount of criticism then some action would be taken anyway.
And in the immortal words of Forest Gump "thats all I have to say about that".