Why is that "necessary"? They want more land so they take yours. Is that 'want" really necessary or just another form of evil with which normal people have to contend? I dunno. It's complicated.
If you've ever read Thomas Moore's Utopia ... y'know, when people talk about want a Utopian society? ... that "idealistic" society would actually invade other nations, if they believed the resources weren't being utilized correctly.
So yeah, most people who talk about wanting a Utopian society have no clue what they're asking for. LOL
I have heard that theory about Pearl Harbor, as well.
Though from what I've seen/heard, they believed there would be attacks by infiltrators. Which allegedly explains why the planes were on the tarmacks rather than under cover. It's easier to protect planes that way, since they are more visible. If you're expecting an attack from above, the planes would have been under cover.
I don't think we could have avoided war.
We were actively shipping material to Britain, and being targeted by German submarines. The next logical step would have been German warships sinking our transports. Totally legal under conventions of war.
We were also interfering in Japan's war against China, going so far as to allow volunteers to fight for China.
So, we were like a guy at a fight ... who keeps hitting one of the combatants. At some point, they are going to hit back.