User blog comment:Dtregle/Jason Todd in Young Justice/@comment-68.89.172.167-20120618172359

i think theyre not mentioned because the show takes place in the timeline for "earth 16" which gave the writers room to tweak characters and storylines to fit the show n their ideas. since not much is established in "earth 16" timeline the writers can basically do whatever they want with characters and stories... jason todd might not have even existed in the earth 16 universe