His colour not relevant? Well to most black people both in and out of America, including me, it is relevant. Read his memoirs and you will understand why. Read about American history, the slave trade, how and why field slaves and house slaves were treated differently, colour coding (e.g. in the Cotton Club black female dancers had to be a certain shade of brown to get employment), the One Drop rule, the Brown Paper Bag rule, the John Crow Laws, segregation, Little Rock School, the rise of the Civil rights movements, Frederick Douglass, Harriet Tubman, Rosa Parks, Malcolm X, Martin Luther King, miscegnation laws, why colleges like Howard and Spelman were established etc.
When you finally educate yourself, then you might realise why him being elected as the first African-American President is important and why it is wrong to try and trivilise its significance.
Now that he is President, we should focus on what he does, not his skin colour. However, please don't trivilise what his election means to many people of all races, colour and background.