The more widely read the media outlet, the higher the probability of the whistle-blower's anonymity getting blown.

Once it's released anywhere the risk of losing anonymity is basically the same in the end. Either it's a troll and will die here or it's true and will be disseminated everywhere. Such a strategy would only make sense if the original poster thought that this forum would replicate the research and publish it with no mention of the original source, but that seems more like the kind of thing an investigative journalist would do.