Don't Ask Don't Tell?

When I enlisted in the mid 90’s, there was a check box on the bottom of some forms that asked if I was homosexual. I was told that the Question should not be answered as Clinton had enacted the “Don’t ask, don’t tell” policy. Prior to this policy, if you checked ‘yes’ in the box, you were not eligible for enlistment. Years later, Obama repealed the “Don’t ask, don’t tell” policy and then allowed homosexuals into the military. If Clinton’s policy was repealed, shouldn’t it have gone back to the way it was before, asking and not allowing homosexuals in? I’m no lawyer, but that never made sense to me. If you have an answer, help me understand.