Japan has a history of militarism, long before the US got involved in East Asia. I think it has to do with Japanese nationalism and ethno-centrism. This will not go away anytime soon, with or without US presence.
Hopefully Japan learned its lessons in WW II, if not history will repeat.
An alliance with the US will not be enough to secure Japan in the future, that is why they are reaching out to ASEAN. But reaching out to ASEAN for defense ties means that Japan has to work with former colonial subjects as partners and coworkers. If Japan can do that, then that will be a positive step and it will open the way for more Asian stability, improved relations with China and South Korea and eventual removal of US bases from East Asia.