Maybe he means that Ken and Roberta were the Pioneers that helped or inspired people like Warren become who they are today. Maybe Warren worked for them at one time. Maybe they colaborated on some projects. I, too, have no idea why he references Warren.
Off Topic:
All I know is Deus Ex was awesome. Its follow-up was frustrating…too many load screens. I want Warren to revisit Deus Ex and bring all the voice actors back. Such a collosal game. Too bad it won’t happen.