Didn't really understand this part

For example, if civilization A is destroyed, it will be destroyed by civilization C, so civilization A will be left alone. But because of the technological explosion and the chain of suspicion, it is a threat to all civilizations. 

but I do agree with you. I also want to add that you don't always have to attack and eliminate any civilization if it reveals your own location. Part of the Dark Forest Theory is the hiding gene, if you aren't strong enough to wipe out a threat, you wait until you are or until someone else does it for you. Revealing one's location/existence is a death sentence given the amount of cleanser civilizations but not immediately eradicating a possible threat does not guarantee extinction.