Since when do Indonesian laws control American citizenship? Whatever Indonesia thinks, US law controls US citizenship.
If, I say If, Obama claimed Indo citizenship status after he was of age, would that be implied consent? Just asking.
Indonesian laws do not control American citizenship, but actions he may have taken under Indonesian law ARE relevant for purposes of determining whether Obama affirmed allegiance to Indonesia so as to lose United States citizenship within the meaning of the INA as in effect in the early 1980s.
For example, if Obama (as a young man and not as a young child) signed and filed papers with the Indonesian government to obtain or renew an Indonesian passport, then that act alone likely constituted the making of an allegiance to Indonesia, since Indonesia required that its passport holders NOT be citizens of any other country.
In contrast, for a country like Israel which permits dual citizenship one is not required to forswear other nationalities to become an Israeli citizen and obtain an Israeli passport.