From whom could the Indonesians be defending themselves? NK and China are the only possible aggressors. Muslim problems should all be internal. Is the East Timor Air Force still in existence?
When little countries start buying sophisticated systems like this, it is nervous making. Like giving a little kid a big revolver.
I will not comment on whether we should or should not sell weapons to Indonesia. But buying weapons from the US is fraught with risk for the purchaser. It generally takes years for the weapons to be delivered and then you have to rely on good relations with the US to get spares and support. A weapon system can be in service for thirty years or longer with upgrades. During that time it is likely the presidency will change hands multiple times and the world situation will change. If the purchasing country wants to do something, and it can be small like allowing genetically modified produce or grain to be planted, and the US objects, the US may render the weapons system useless by lack of delivery or support.
It is less risk to buy weapons from Israel or Russia.