So regardless of how many people are being hurt by not outing this person. Keeping that person safe and allowing them to come out themselves (assuming they will at some point) is more important than exposing the hypocrisy of a politician and the shaky foundation of policies they are creating/enforcing? I'm not talking about some random person or random celebrity or anyone else for that matter whose personal life/sexual preference is inconsequential to the general population.
Who stands to benefit from outing a public figure though? Nobody, really. Best case scenario, said politican resigns and is replaced by someone who isn't gay who continues said policies. That still inflicts pain on the community as a whole because it reinforces the fact that there is a certain Way to Be Gay. You don't have to be out to be gay.