Did they do anything about that?

One small problem with that is, and that is if someone gets a fine for feeding birds, the media (most notably the Herald Sun and tabloid shows like A “Current Affair”) and politicians would be the ones complaining, calling the Government of the day “money hungry” and issuing fines willy nilly, even if there is a sign saying do not feed the birds.

As you rightly allude to this isn’t a pigeon problem, it’s an architectural one. We regularly build infrastructure that allows or encourages these results, just like we also build unfriendly infrastructure (poor weather cover, poor layout, poor accessibility) to avoid human elements. People / environment first design should be the goal.