It should be appreciated that this whole effort to hold leaders of states criminally responsible is a rather radical challenge to territorial sovereignty and a repudiation of the whole related ethos of 'sovereign immunity'.
On the cautionary side, Universal Jurisdiction could be used to achieve some kind of ideologically motivated criminalisation of 'the other' that would discredit and derail a constructive effort to develop a credible meta-law that governs the behaviour of leaders of sovereign states.
There is no effort to acknowledge some equivalent accountability by associating "terrorism" with all violence that is deliberately aimed at civilians, either directly or as foreseeable effects of violent acts, whether the actor is a non-state individual or group or the state.