The grounds for medical exemption against vaccination in Australia include active COVID infection where vaccination may be deferred for 6 months. Djokovic has said he’s opposed to vaccines so he’s not deferring vaccination.

Then after testing positive he decided to break Serbian isolation rules and deliberately risk the health of others. Then his visa form was found to be untrue regarding foreign travel.

In the middle of a public health emergency where Australians are required to follow the rules and do their bit it seems reasonable for the Government to decline Djokovic’s request to be a guest in their country at this time.