Japanese treaty parity could become a fiscal trap

Would treaty parity have prevented Japanese militarists from exploiting resentment over naval limits?

Not necessarily; Japan might instead have strained its economy trying to match two much wealthier naval powers, creating a different source of instability.

Permission to build does not mean that every navy will complete its allowance. Britain could accept American parity because Congress was unlikely to fund the whole ceiling in peacetime, while the Imperial Japanese Navy would try to reach it. That effort could leave Japan financially exhausted and heavily armed. Treaty ratios therefore reflected economic capacity and political risk as well as prestige.