- where the agent is not morally competent
- where the degree of "torture" is disputed
On the question of the moral 'competence' of the perpetrator, often in heinous crimes the accused will use a defence that they had "no choice", either because they were coerced (e.g. the Nuremburg defence) or they suffer from a mental illness / deficiency. I personally don't think this overcomes the generalist position that torture is wrong, but it does seem to support the particularist point of view that context is always an issue when deciding on moral issues.
When I started typing my response I began by thinking your second argument is less of a problem for the generalist but, on reflection, it seems also to be a good one. One could argue that the moral principle still stands - any argument about whether an act constitutes torture is separate from the argument about whether torture is morally bad, but I can see that there could be significant disagreement.
So to defend my generalist position I need to frame the principle carefully - i.e. "a clear and undisputed case of a fully competent person torturing a baby purely for fun is bad". On the whole I don't feel it is necessary to do this because the vast majority of people know what is meant by "torturing babies for fun is bad" and the arguments are around the facts of the case and not the moral principle behind it.
I think quite a lot of moral principles are generally true, and the debate is mainly over the facts of the case and not the validity of the principle.
A lot of Dancy's variable 'context' will determine the facts of the case (i.e. did the person make a free choice, how much damage is being caused) and not the validity of the moral principle.
I mentioned earlier that a lot of moral principles are tautologous - such as "injustice is bad". Surely it is part of the definition of injustice that we think it is morally bad - take the OED definition for example: "The opposite of justice; unjust action; wrong; want of equity, unfairness. With an and pl., An instance of this; an unjust act."
How can anyone defend the position that injustice is good without contradicting themselves? I don't believe there are circumstances or contexts when we can say that injustice is good (in itself).