Law of Destruction was most likely called the law of destruction because it could only destroy everything it comes in contact with, however, this alone is not the reason. It is called the law of destruction also because of the existence of other laws. The existence of the other laws ensured that the law of destruction would always be in a state of continuous destruction!
It could destroy all sorts of Laws. Naturally, it could also destroy existences under these Laws, such as any law skill, any person, any world, or even the entire universe.