Actually it makes perfect sense, given that many Death Knights were former paladins. And since many of them were raised unwillingly and feel remorse for what they did under the command of the Lich King, individual death knights do not exactly “represents all what is death, unholy and deceases [sic]” . Furthermore given the co-operation between the Argent Crusade and the Knights of the Ebon Blade, I am sure there was a lot of time for people in the two groups to form relationships. So in summary: u mad, bro?