I am not trying to prove any bias (or “prejudice” as you mentioned earlier) at all.
The question …can people have a secular based objection to same sex marriage?
The answer is yes. They don't have to be of any religious belief to object.
Does not matter if their secular reasoning is any more or less “logical” than one who goes to church three times a week. Ut does not matter in the least if it disagrees with what one would define as a "illogical".
The point is that there are people that oppose same sex marriage not based on religious beliefs.
To say that ONLY those that object have a religious basis is wrong.
Yet you cannot provide that this is a halmark argument from atheists or agnostics? Can you provide that like many arguments against gay marriage, this one isn't masked from it's roots?
The biological and "social" argument laid forth here could be based upon religious beliefs as someone that was completely devoid of religion SHOULD be able to see the other scientific and social counterpoints that easily disprove said argument.