I'm coming at this from a slightly different angle. Growing up, I heard all the bigotted comments about gays and lesbians (my Dad is career military). When I recognized my sexual orientation, I felt compelled to come out to my family. I did this to stop the comments and to educate them that, yes they do know a lesbian.

As I further learned what makes me tick sexually, I was again faced with their comments (why is it the that the only float that makes the news from the Gay Pride Parades is the S&M one?). I again felt that, for my own self respect, that I had to defend my desires.

Building on what Polaris said in an earlier post, people make the disparaging comments about things when they don't know any better. Your father may feel free to speak as he does, because the only BDSM people he's seen have been patients or case studies. That's a limited pool to infer knowledge from. Making him aware of someone who is a well integrated person and involved in the community will be to his benefit. There is the famous phrase by Ernest van den Haag, a psychotherapist: "I am reminded of a colleague who reiterated "all my homosexual patients are quite sick" - to which I finally replied "so are all my heterosexual patients.""

Despite how much help to him and his patients it might be, your coming out as a submissive (or Dominant or masochist, etc) is a strictly personal decision. You've got to weigh all the potential consequences against the benefits. I wish you all the best in whatever you decide.