The Notre Dame fuss

Last I heard, Bishop John D’Arcy was still refusing to attend Notre Dame's commencement because President Obama was speaking at their commencement. How childish!
He is offended because President Obama doesn't hold his same value system in all areas and if that is the case, he will not be attending the graduation of a prestigious university in his diocese. Is this what Christians do? Do they say that unless you believe as I do I can have nothing to do with you? Is that what Christ did? Didn't Christ sit down with tax collectors and prostitutes? Even - gasp! - Roman centurions? Who are we to act differently? Is this how one proposes to bring others into the fold by sticking our fingers in our ears or threatening to take all our marbles and going home when no one wants to play by only our rules?
I don't think so. This is our President. I think any school is lucky to have him speak at their commencement. People stood in line in the cold for hours on Inauguration day and Notre Dame attendees get to sit comfortably in good weather to hear one of the greatest men of our time.
And apparently, this bishop is not alone in his thinking. I don't understand the logic of anyone who condemns a peaceful man like President Obama but thinks a man who kills under false assumptions and allows torture is OK because he professes to be a conservative.