when questioned by o'brien, winston and julia state that they are willing to commit many crimes, including the killing of innocent people. do you think that this is justifiable, given the terrible nature of the party?

They both feel that the tyranny of the Party outweighs any horrible sabotage they might enact. The attributes of this ideology is that the means justify a particular end. In the case of this particular dystopia, I would think that anything is better. So, yes I would justify it. The outer party kids were rather vile creatures anyway!

I most certainly think this is justifiable, indeed given the terrible nature of the society they lived in!