why do people think BDSM is not good? I feel it is very natural and I love to serve a superior female

can bdsm and love can happen with same person? i say yes

Didn't hear anyone say BDSM is not good.
And sure it can be both BDSM & love relationship. If you really are in the scene, you should know this. So I find your question bit strange.

its a matter of respect

people can distort BDSM, ,they can distort 'biblical' marriage too

I think people often think of BDSM mainly as being brutalized, demeaned, ,,,etc,, and certainly some in the lifestyle will use it that way

but when used in love and respect, whatever the label, allowing the trust of another to make decisions, and accepting the responsibility of being that other always with love and respect

is not a bad thing at all,,,

Most ppl don't know the first thing about BDSM, they only know the extreme stuff they sometimes get to see on telly.
That's not the kind of ppl you want to hang out with, get information from etc. Just find your own circle of ppl who are into BDSM. You can find those online too, plenty of site, fora etc on BDSM.
Just be selective if you are going to find yourself a mistress. You really must have a good feeling about her and be able to trust her. If there's even so much as the slightest trace of doubt, do NOT go for it!!
Being a Dom/me is quite a serious responsibility, so find someone who can handle that, especially if you want to be a slave instead of a sub.

Good luck!

your answer is perfect, would love to have domme like you... :)-