Er, can they guarantee today that the pilot is not suicidal, drunk, a control freak, or incompetent?
No, but put any one of those character flaws in the control room on the ground in a control booth, which some are suggesting, then watch the carnage. With software flaws there are no opportunities to correct them before they manifest themselves. Mental health is a society wide issue and amongst pilots it is being addressed. Drunk and drugged pilots are being sorted with drug and alcohol testing and they are being caught. A control freak? You would have to clarify that as to how that leads to an accident. CRM took care of that problem years ago. Incompetent? All walks of life even, software engineers. I am not saying that human error can be completely eliminated but from what I can tell "software glitches" can be just as fatal and fully autonomous in their manifestation and catastrophic results. Where the pilots came in handy were on aircraft such as the MAS 777 and QF 330 off the coast of Western Australia.