If McCain had won I'm sure there would have been plenty of references to him throughout the day. Simply referring to someone in politics doesn't mean you are being inundated by whatever politics they believe in. Referring to Obama was a way to make the speeches current and specifically relevant to the time in which our class is graduating; be it "Drew Kindle" or Obama - they are attempts to be contemporary.
If hearing his name mentioned or the fact plainly stated that he is the first black president in our history offended you, well then I'm sorry. In my humble opinion, if anything was offensive, it was the shear length of ceremony. Everything was incredibly long and drawn out, except for Seth's speech which was the highlight of the whole event.