Sweeping Khalidi under the rug?

A few days ago, I published a piece by Bret Stephens that suggested that President Obama's views of Israel have been mostly influenced by radical Leftist Jews, particularly one rabbi, Arnold Wolf. Sunlight points me to this piece by Martin Kramer from 2009, which indicates that Wolf alone cannot be blamed and that attempting to do so is sweeping Rashid Khalidi under the rug.But how is it possible