The difference is here, the funding was supposed to be assessed by an independent panel, but their recomendations were thrown out and changed by the minister.
IMO that's the clarity of the difference between a party deciding what their campaign/policies will be and where they will allocate funds vs corruption of a scheme.
We don't have an expectation that parties run their campaign decisions past an independent panel, it's just ludicrous. East-West Link decision, whether you agree with it or not, that's a decision Vic Labor made in their campaign. That's not corruption. To that extent, both sides of politics will maximise their vote by targeting bell-weathers or maintaining their own seats vs funding seats they will never win. It's just blatant obvious politics.
A fund that is set aside for a particular purpose to be assessed by an independent panel and that independence is discarded? That's an entirely different proposition and this is where corruption starts to become an issue. When something like this occurs, it's usually bipartisan/across politics that people become unhappy hence the bipartian support for inquiry.