I think Owners Corporation insurance IS a form of public liability insurance. The problem here is that the people running the Owners Corp had no idea of their responsibilities and came up with all sorts of excuses for not doing what they should have done on Day One: fixed the problem then claimed on their insurance.
Considering the size of the building (28 storeys) it's alarming that the people running it are just making up the rules as they go along when a phone call to their strata manager could and should have sorted this out immediately.