The deflectors in question were to prevent water spray being ingested by the engines as stated above.
From what I know about French Law, if an aircraft drops something on the runway which causes an incident, the owners of that aircraft are accountable. Not taking into account the design flaws and the fact that the tyres puncturing the fuel tanks when bursting were known issues, if the FOD was not on that runway that plane would have been put in the situation that resolved into the crash. Right or wrong, that's how the French government see it.