If you had a friend who stole your wallet one day. Then you discovered who it was. Would you accuse the rest of your friends for being wallet thieves too? The fact that you are considering on arbitrarily dispensing justice to every ogre based on the acts of a few isn't very Lawful.
You are going chaotic.
Now just killing every ogre for the sake of making the world a better and safer place I would deem to be evil. You should strive to at least be the better man and let be. Or if your are zealous enough to do a good deed how about doing missionary work and teaching the ogres right wrong?
As a Lawful Neutral character and ignoring any racial prejudices I personally wouldn't give a rats ass whether the next ogre lived or died. Hopefully they wouldn't tempt my blood-thirst.
Remember the "road to hell is paved with good intentions".
Now to play devil's advocate for the Ogres here:
Maybe the civilized world is encroaching upon the ogres and they happened to defend their territorial claims. Being good denizens of the world they follow a philosophy of "want-not waste-not". So they killed the intruders. Chewed on their bones. And made furniture of their victim's flesh. Druids everywhere would be so proud that not a single scrap was wasted.
This reply is made with scant information provided by the situation. I'm trying to not take your situation out of context.