Not at all, it's clear in all those cases that they killed people. But that doesn't automatically make them totally culpable.
In the case of Rudukabana, he had been under the care of MH services but stopped engaging with them. He wouldn't have been under their care if he wasn't unwell, so I couldn't be confident that he was 100% sane and responsible for his actions. Adam and Saadallah had also had involvement with MH services. In a different climate, they may all have succeeded with a diminished responsibility defence had such been put forward.
These cases remind me of the Valdo Calocane case. The enquiry into the MH services involvement with him found failings in his psychiatric care: Valdo Calocane MH report . Of course, we'll never know if things would have been different if there had been a more assertive approach to his care and treatment, but it raises a question.
I worked in a non-medical role with MH clients for 18 years. Over that time, services were cut and cut, and clients who used to have regular contact and input from MH professionals were getting nothing unless they went into crisis, someone noticed, and they engaged with services. My colleagues and I were often the first to raise concerns with local MH teams, because they weren't getting regular support. It really shouldn't be down to homelessness, resettlement and welfare rights staff to raise alerts about the deteriorating mental health of people who are under the care of mental health teams, MH services should be checking it out themselves.
I really wouldn't want to live in a society that fails to address deteriorating mental health in people who are already under the care of mental health services, and then executes those people when it all goes tits up.
In the Bendall case, it rather looks as though probation dropped the ball, again because they were overstretched and struggling. Bendall: probation review
But this is what happens when governments cut funding for these essential services. There was a time when mental health and probation services had assertive outreach teams that would monitor clients regularly and get them admitted to hospital or recalled to prison if they considered it necessary. That work just isn't being done these days.