The media bias is evident when you look at who and why they attack certain individuals. Biden has gotten away with a lot of stuff. He basically groped a woman in public, in front of cameras, and the reaction was "Oh, Biden....", but when Dan Quayle only accepted a different spelling of potato at a spelling bee, he was vilified. Another example of bias is look at DHS funding: some media outlets are blaming Republicans of denying funding, yet it's Dems that are blocking the vote through parliamentary measures because they don't have the votes to outright block it.
As I've seen it, the Koch brothers are not for gay marriage, one has said he's basically fine with it and doesn't get why everyone's in a big fuss about it.
I, for one, tend to be fiscally conservative, yet socially liberal or, rather, laissez faire. I don't care to subsidize others lifestyles, but I won't comment on or condemn others' lifestyle choices. However, I'm willing to state that marriage is not a constitutional right, and as such, should be left as an issue of states' rights. I'm also willing to state that the primary reason this is an issue is because the federal government grants certain privileges (nominally in the form of tax breaks) to such qualifying "couples". The argument to extend such protections is under the 14th Amendment "equal protection" clause, yet neither sexual orientation nor marital status is listed, under that amendment, as protected classes. Thus, if you extend that qualification to same-sex couples, you're still alienating another class: single individuals and still violating the spirit of the 14th Amendment. What it boils down to, if you treated all people equally, as individuals, regardless of marital status, gay or otherwise marriage would be a non-existent issue.