While not the entirety of the under-representation situation, the pipeline is absolutely the biggest contributing factor. Take a look at any CS class today and

While not the entirety of the under-representation situation, the pipeline is absolutely the biggest contributing factor. Take a look at any CS class today and you'll see a sea of white and east/south asian faces, an almost no black students – I took several CS courses at the University of Washington a couple years back (staff perk) and out of ~500 students perhaps 2-3 were black. No amount of corporate diversity training or preferential hiring is going to fix that ratio.