But that was the crux of my question to you - is the simple instruction to "do unto others as you would have them do unto you" sufficient? Clearly not, given that people's actual desires are widely varied, and one person may desire to be treated in such a way that another person would find to be revolting or even criminal.
You are confusing the physical actions with the emotional responses. When we talk about torture we are talking about creating emotional suffering. The actual physical methods for inducing that suffering are the means to that end.
For S&M, the Golden Rule does fine. The "do unto others" is creating pleasure when requested as part of a consenting relationship. I don't think anyone would classify that as torture.