Dianne Feinstein has the highest security clearance in the senate and would know the specifics of the Bin Laden hunt.
I think their point is that the film depicts specific intelligence being gathered using torture, when, in fact, that specific piece of intelligence may have been gathered through other methods. Of course, the senators can only complain about this in the most general sense.
I don't care. I would rather believe that many bad guys were tortured in the hunt for Bin Laden. Hell, I'd rather see Bin Laden shot while he begs for his life.