Saying the quiet part out loud

The phrase already has the opposite meaning. It's used primarily in political contexts, where someone admits to an unsavory position for which there has been a less unpleasant alternative reason. For example, citing a racist reason for a policy, when the tacit agreement among proponents was to not say that "out loud".

It is good policy to be explicit when you should be explicit. But as a political strategy there is a reason not to say the quiet part out loud, at least not yet.