I don't think that Mosely being exposed was in the interest of the public as his private sexual proclivities had no bearing on his work nor was he claiming publicly to be something which he wasn't; OTOH the Pakistani cricketers were breaking the law if they were match-fixing (or even spot-fixing) and defrauding the bookies. As for testing the security of institutions, there is a time and a place for this - and probably a better way to do it (for example with a prior notification to someone in authority and/or a deposition placed with a lawyer in advance). Cash for questions was also breaking the rules of Parliament and thus was in contempt of Parliament which is illegal.
It is actually quite a straight-forward test to apply...