Because in common law there is a principle of 'natural justice' that is designed to make sure that all parties have equal and uninhibited access to the legal sy

Because in common law there is a principle of 'natural justice' that is designed to make sure that all parties have equal and uninhibited access to the legal system. A conviction in absentia would be considered by most lawyers to be as bad as a trial that proceeded where the defendant was assumed guilty to be proven innocent.