Decades after homosexuality was decriminalized in Britain, the government announced on Thursday that it would posthumously pardon thousands of gay and bisexual men who were convicted, in essence, of having or seeking gay sex. Since 2012, men with such convictions who are still alive have been able to apply to have their names cleared. The men were convicted — tens of thousands of them — of crimes like buggery, gross indecency and loitering with intent. They had been arrested in bars, coffee houses, bars and public bathrooms, and sometimes in the privacy of their homes and with their partners. In many cases, their only offense was seeking intimacy with another man.