Prior to DADT they were actively hunted out and removed from service - often court-martialed. DADT actually allowed them to serve as long as they kept their sexuality private - and commands were not allowed to pursue investigation of homosexuals (the 'don't ask' part) as long as they didnt overtly disclose their sexuality (the 'don't tell part')...and if they did tell their discharges were administrative only, not a judicial action (courts-martial).