Henkster wrote an admirable essay that he reposted not long ago describing the iron logic that led the Germans to attack Russia when they did, that I won't attempt to reproduce.
The Japanese were crazy. Because they were determined to seize at least Eastern China, they got crosswise with the United States and we imposed embargoes that were somewhat biting. They had also invaded French Indochina.
Yamamoto and the Navy opposed the China war, but the thought of stopping their war on China was anathema to the Japanese Army leaders.
Their logic was that because of the American oil and scrap embargoes they needed a source of oil and minerals. That they saw in Malaya and the Dutch East Indies. But athwart the line of communication south lay the Philippines. Therefore, in addition to the targets, the Philippines had to be taken. But that meant war with America.
The Navy and Yamamoto in particular opposed an attack on America. Indeed, they had opposed the China war too. Yamamoto was educated at Harvard and had spent several years in postings in the U.S. He was well aware of American industrial superiority and knew that Japan could not defeat America in a war. He was not, however, able to dissuade the militarists and particularly the Army from war. There are many times in history where a military deludes itself into the belief that it's will and fighting ability would enable it to defeat a superior force. By 1914 the French had convinced themselves they could defeat the Germans despite numerical inferiority.
So, the Army won the debate. Yamamoto then devised his Pearl Harbor plan in the belief that if the U.S. fleet were destroyed that would give the Japanese a 2-3 year head start to conquer their empire and dig in to meet an American counterattack. It was their only play and we know how that worked out.
I don't think it mattered that Hitler declared war on the U.S. It was obvious after Pearl Harbor that we were in the whole world war and Roosevelt fully intended a Europe first strategy. So, I won't violate henkster's law and speculate what might have happened if Hitler hadn't declared war.
Britain also declared war on Japan, so that basically removed any restrictions on aiding Britain, only a matter of time before the Germans would have attacked our ships sending aid to Britain, giving us the Casus Belli with Germany.
I’ve read somewhere that Hitler viewed the U.S. with derision, thinking we were a “mongrel nation.”
In one sense, the Japanese were crazy. Your comparison to French doctrine of World War 1 could not be more on point. The French deluded themselves into believing that an offensive spirit, or elan could somehow overcome the physical laws of nature; that being no amount of elan will keep a machine gun bullet from killing a soldier. The Japanese thought exactly the same thing, only they called it seisin. If you really want to laugh at the French, you can point out that their tactical thought was no different than the Zulus who fought the British, believing that their witch doctors had magic spells that made their shields of grass and wattle impervious to British bullets.
Despite having the lessons of the Zulu wars and World War 1 to ponder, the Japanese plowed ahead in their belief that a warrior ethos was more than enough compensation for technological and industrial inferiority. Yeah, that was just plain crazy.
For the rest, it was a simple miscalculation of just how powerful the United States really was. Even Yamamoto did not realize just how many ships and planes the United States was going to crank out once it got fired up.
The real question of a "what if," which violates Henkster's Law, is whether the Japanese could have attempted to seize lightly defended British and Dutch colonies without attacking the Philippines, and triggering a war with the United States. Interesting question, but no, that wasn't how the Japanese were wired.