By releasing the information that they captured those men and found the plans, it seems to me they gave up a potential advantage. If it were kept secret they might have been able to thwart the plans and take more terrorrists down. Now that the terrorrists know we know, they will make new plans; and we will be back where we started before picking up those men: wondering what will come next.
I realize that this information comforts people. "Look, we captured more terrorists and now know their plan". But I'd much prefer the terrorrism be stopped without my knowledge than to know what their plans USED to be.