[mc32]

In theory you’re right. In reality we have people who seek power or in some popular cases a popular mandate to cause change or negate change through war (many civil wars, for example).

This isn’t unique to people. Lots of organisms and even systems operate in similar manner.

[4ggr0]

Yeah you're right, there will always people who start wars, or would like to start them. But if the question is, "Is war necessary?", then my answer is no. Maslow's hierarchy of needs does not contain war as an item, our earth moves on fine if no war occurs, etc.