It's a very good question. Cross examination is a fundamental part of the trial process. Evidence, including witness testimony, is examined to demonstrate it's veracity or otherwise. Witness testimony can be unintentionally unreliable even if given with absolute honesty. Basically letting someone stand up in court and say whatever they believe to be true without question or examination is a very... challenging thing to contemplate.
I appreciate that taking part in a trial process when the crime that has been perpetrated is so traumatic - rape, GBH, attempted murder for example - is a difficult thing and does in fact put some victims off coming forward at all, which we must try to mitigate as much as possible. And I think the idea of a the accused questioning the alleged victim themselves is abhorrent. But the trial process is about trying to get to the truth. We can't throw the baby out with the bathwater, as it were. If we're going to allow this, we should at least include the stipulation that the defence should be allowed to submit a list of questions which the witness should be required to answer, also by video if necessary.
