This has nothing to do with coming(came) out. As VDH points out, this is not a revelation, these issues were significant at the time and they were widely discussed. Obviously, there are a lot of people, or a lot of freepers, who don't remember these things/events/issues. We actually know the whys and wherefores of Clinton and Obama opposing the Iraq surge and we know the whys and wherefores of Clinton and Gates supporting the surge in Afghanistan while Biden supported less of a surge in Afghanistan
As for telling the truth, Gates is not talking the truth, he is talking the position he took on specific issues, which would have been different from the position that others took.
BTW, this book is not Gates' first memoir book. His first memoir covered his time from the 70s thru GHW Bush, which was published in the late 90s. In that book he published the info about Jimmy Carter and Brzezenski giving the foreign aid money to the political opposition in Afghanistan, which led to the Soviet invasion of Afghanistan. Gates knew about that because he served as Deputy National Security Advisor under Brzezenski.
Which contributed to the dissolution of the Soviet Union. So, although it pains me to do it, I'll score one for Carter and Brzezenski.