Matt Winkelmeyer/Getty ImagesRobert Downey Jr. is facing social media backlash after thanking Mel Gibson in his SAG Awards speech.While accepting the award for Best Supporting Actor for his performance as Lewis Strauss in Oppenheimer, Downey took a moment to shout out a handful of stars who had impacted his career. Cillian Murphy, Emily Blunt, Jodie Foster, and Annette Bening were among those named, along with Gibson.Gibson has been criticized for a number of controversies, including racist rant