In a statement Monday about the latest DOJ brief, he said it “makes clear that my Administration believes that the Act is discriminatory and should be repealed by Congress. I have long held that DOMA prevents LGBT (lesbian, gay, bisexual, transgender) couples from being granted equal rights and benefits.newsmax.com
“While we work with Congress to repeal DOMA, my Administration will continue to examine and implement measures that will help extend rights and benefits to LGBT couples under existing law."
As for the Justice Department, its brief reads: "This Administration does not support DOMA as a matter of policy, believes that it is discriminatory, and supports its repeal."
I think that he did this to play up to his base, the far-left.