wedrifid:

But you did ask "what basis should" while Robin was just asserting a controversial is.

I probably didn't word my above comment very well. I am also asking only for an accurate description of the controversial "is."

The fact is that nearly all people attach great moral importance to these issues, and what I'd like (at least for start) is for them to state the "shoulds" they believe in clearly, comprehensively, and coherently, and to explain the exact principles with which they justify these "shoulds." My above stated questions should be understood in these terms.