Straight people flaunt their sexuality all the time, but the fact is not noticed.
Every time heterosexuals refer to their wife, boyfriend or whoever; every time they speak admiringly of a nice-looking TV star, or check into a hotel together, or open a joint bank account, or choose to be called Mrs, or hold hands in public, they are announcing their heterosexuality to the world. This "flaunting" attracts no attention simply because so many people do it.
All the mundane acts listed above will usually be regarded as provocative if a gay person does them. Mercifully, thanks to the trail-blazing work done by many prominent gays, the simple act of stating that one is not heterosexual is increasingly not regarded as provocative - witness Chris Smith or Angela Eagle.
But tolerance is not acceptance. Until being gay causes no more of a stir than being left-handed we will hesitate to be open, but acceptance can only be won through refusing to hide. Most of us can only make an impact in our own little circle. Mr Mandelson, however, is uniquely placed to win an advance towards acceptance simply by being openly who he is while carrying out his work. It is a pity that he chooses not to do so.