Not cool. USA was already supplying literal ship loads of weapons to Europe (UK) before the pearl harbour thing. They were risking U2 infested waters to supply essentials.
Pearl Harbour didn't even necessarily need them to engage two enemies on two fronts. They could've just gone after the Japanese and not bothered with Mr. Toothbrush Mustache.
America was not a perfect nation, but good men within their powers tried their best.
They were profiting from selling weapons. There was nothing altruistic there.
They could have made more money if they were selling to all sides then.
They lost good people and ships sending supplies and weapons to UK. On credit. They wanted to settle the accounts, but not make money up front. They knew there was a chance there would be no UK, and thus no one to settle the debts.
One of the reasons Japan did Pearl Harbour was because US had economically sanctioned them. They weren't able to get any rubber or oil for they resource poor Industrial 1/2
nation. They were looking at a collapse unless they acted and took over south east asia or all of china.
Now, the reason US had sanctioned them in the first place was because of the atrocities they were committing in China.
That was the reason they attacked US, to scare them into doing nothing as they pillaged all of SE Asia "Prosperity Sphere".
America was far FAR from good during those days. But America is many people. And they tried everything they could to stop them.