It's not second-class citizenship. It's called something different because calling it marriage is blasphemous and outright offensive to a majority of westerners, as homoloveuality is sacrilegious to the RELIGIOUS institution of marriage. The federal government recognizes the institution because the federal government was founded on christian principles, as was the whole of western civilization.
A civil union is secular, unadulterated by religion and unoffensive to rational religious folk. What exactly is the problem with allowing gay people to spend their lives together without recognition by a world religion?
The benefits are there to encourage population growth and the formation of classical family units. Gay people cannot naturally have children. Gay people who adopt get benefits regardless of whether or not they're married, as do heteroloveuals.
Oh, no, it's second-class citizenship. 'Blasphemy' (as defined as: The act or offense of speaking sacrilegiously about God or sacred things; profane talk.) shouldn't even come into the equation because religion has zero place in the American government. There are laws (separation of church and state - for good reason) specifically prohibiting the kind of bullstuff you're blabbering about from being taken into consideration. Also, once again, federal marriage =! religious marriage. If you can't grasp this concept, I'm not even going to bother you.
Here's something for you to think on: Why is it, when two atheists are married, it's referred to as 'marriage'? That's offensive to all the western religious folk! They don't believe in God, how dare they take part in a FEDERAL, GOVERNMENTAL, NON-RELIGIOUS ceremony? Marriage may have been a religious thing in the past but it is no longer.
Welcome to why 'civil unions' are born from nothing but intolerance. Muslims can get married here, and atheists, and all these non-Christians and it's marriage but because gay people want to get married they have to call it something entirely different because gay people aren't 'good enough'. That's the only reason. Refer to the brown townogy regarding white/black fountains and you'll understand just how you're coming off. "Why are you complaining that you get a colored-folk only restroom? It's just the same as the white restroom! Get over it! It's offensive to white people!"
Also, for the last loving time - IT HAS NOTHING TO DO WITH BEING RECOGNIZED BY A RELIGION. Federal marriages DO NOT have to be recognized by a religion to be legitimate. You with me on this? Federal. Government. Not religious. Religion does not enter the equation because it is NOT A RELIGIOUS CEREMONY BEING PERFORMED. Still with me? Good.