I would not consider democracy a goal. I would consider it a means to the goal of a reasonable, safe, productive and stable soceity.
I also don't see what's wrong with cherry-picking Federalism. Different situations and issues can require different approaches.
Lemme see a minute here... interesting, Kerry voted no on the Defense of Marriage Act. But it passed anyway and is currently in place. Challenge may render this law unconstitutional but barring that it could be a state issue. States are the entities that give out marriage licenses after all.
But that's not my point, I find it interesting to find out and discuss Kerry's views but I'm not Kerry, I don't agree with Kerry (on this issue atleast) and he's not here to explain anything so I'm going to move back.
Well, not too far because my main point was that I see no distaste, I do not see and have not seen him complaining; there is no problem to be fixed.
Also, to correct (slightly) a previous statement, allowing marriage (of any kind) does indirectly hurt those that aren't married - in areas such as tax burden, insurance coverage and rates, child custody and reduced pool of available singles (and others that aren't coming to mind right now.)
So technically it is incorrect to say "letting consenting adults - no matter what sex they are - marry hurts no one" but it is not incorrect to say that same-sex marriage hurts people only in the same sense that mixed-sex marriage hurts people.