There's public outrage over the Kennedy Center's policy of selling cheap standing-room tickets for sold-out performances only. "Frankly, it is our goal to sell every seat in our theaters before we sell standing room," said center spokeswoman Laura Longley. Last Saturday nine standees picketed in protest. "This is a public facility that the managers operate in trust for all of America but their policy seems to be one of exclusion," said standee Daniel T. Ingram. "They're trying to make it a private club for the rich." Longley said the center makes many low-cost seats available through a variety of programs. "It is not an issue of the rich versus the poor . . . There are no plans to change policy in the face of this massive uprising." The center has always had the policy for theater, and put it in place for opera and ballet a year ago. The Washington Opera continues to sell standing-room tickets, sellout or no sellout, because director Martin Feinstein believes in the tradition and has resisted pressure to change. Ingram wonders why, if the Kennedy Center management likes money, it turns paying standees away from performances that are not sold out.