They do not deserve to be protected by the laws of war...
The moral duty to respect a basic level of humanity, which the Geneva Convention embodies, must be retained
There is no moral duty to respect the humanity of terrorists. Terrorists themselves do not respect human rights. By attacking civilians, they breach the terms of the Geneva Conventions and international human rights law. They do not deserve to be protected by the laws of war because they do not behave like a military organisation. If they do not comply with the laws of war there is no reason why they should enjoy the benefits of the Geneva Conventions when they are detained.