Robert Redford, who rarely if ever articulates his liberal sentiments at the Sundance Film Festival, which he founded, castigated the current administration as he opened this year's festival Thursday night. Redford declared that the entire country had come together in "a spirit of unity" after the 9/11 attacks in 2001. "We put all our concerns on hold to let the leaders lead," he said. "I think we're owed a big, massive apology." His speech amounted to a prelude to the opening film, the documentary Chicago 10, dealing with the leaders of the angry anti-war demonstrations that raged during the Democratic National Convention in Chicago in 1968.