On whose authority do Nancy Cope’s religious views have “no place in this debate” on same-sex marriage but Dr. Amesh Adalja’s do?

I’m referring to Adalja’s Jan. 21 letter to the editor.

The Creator of human life created people male and female. Is there any other explanation for this gender differentiation in evolution?

Without a joining-together sexually, there would be no humanity around to debate the issue. This joining-together of the sexes has been known historically as marriage in our culture and in our dictionaries — at least until recently.

Would somebody please explain why the same-sex people must call their joining-together “marriage”? Why not call that “specific type of contractual agreement between consenting adults” a civil union?