Of course the defence have to rebut the state. The burden lies with the sTate to prove their version of events occurred beyond all reasonable doubt, thus it makes sense to cast doubt on the state's version.
Particularly in a case such as this where there is limited room to manoeuvre over what actually happened. What shimmering piece of proof are people expecting the defence to come up with?
So.
Some witnesses say they heard a woman scream. Witnesses closer to the scene say not.
Prosecution alledges that OP's emotional state is insincere and adapted for effect. Several defence witnesses indicate that OP was and continues to be distraught.
With the ballistics, the biggest thing Wolmarans is doing is casting doubt on the State's assertions.
It's all about chipping away at the certainties asserted by the state.
Also, of course the defence are responding to what the state have said, that's how it works and why the state have to show the defence what their case is and why the state goes first.