What happens before an outrage like those perpetrated in Paris is that someone selects the target and associates participate to a greater or lesser extent. That is to say, there is deliberation leading to intention or indifference to civilian casualties. A military or industrial target could have been selected but wasn’t; the decision is to kill civilians. In short, there is a wilful choice to commit a crime against humanity.
Because a crime against humanity is essentially target selection it cannot be justified, lessened or even explained by reference to context or circumstances. There are, however, thinking people who want to explore the context of particular acts or campaigns but there are also those who want to use context to deflect attention and responsibility away from the deliberate commission of mass murder. When people go down the latter route or allow themselves to be drawn down this route, the objective is selective approval of some crimes against humanity.
When a member of an organisation that already supports crimes of this nature, discusses context, they cannot be taken seriously. They are merely seeking consistency in trying to find circumstances in which a crime against humanity is defensible.
Listen at about 10.5 mins into the link below as Mary Lou McDonald of Sinn Féin places the Paris attacks in context: alienation, poverty, invasions in the Middle East. These are outrages in themselves; they are the causes of conflict but they are not the causes of the mass murder of civilians. However, if the pretext for mass murder in these islands was “the British presence”, it would be inconsistent not to find a pretext for similar in Paris.