As someone who refuses to allow games, movies, music and other forms of media (whether I like it or not) to be used as an argument for "influencing" a nutjob to be a nutjob, I honestly can't hold Malema responsible for the actions of some psycho.
On the other hand, it can be argued that unlike media, politicians are grand manipulators whose actions, views and opinions can spark uprisings, violence and other nasty things and should therefore be held accountable for any damage that their nonsense might incur.
But, then again, no-one can tell what a nutjob would interpret from any piece of information, take to heart and do because of that. But then, the interpretation is that of the nutjob. Saving, of course, that the nutjob is a nutjob and cannot be expected to think like a normal, rational individual and the responsibility would, of course, then be on the instigator for manipulating the vulnerable psycho.
Meh... I think I'ma go have some tea and leave this argument to the professionals.