Do Javanese and Indonesian mothers fondle their infant sons’ genitalia? This is done in Arab culture, and might explain a lot.
In the far East, Islam is considered Western. It believes in world conquest and proselytizing by force, which no self-respecting Hindu or Buddhist would want. Shinto-ists aren’t even sure why they do those rituals altogether, so to them the idea of proselytizing for Shinto would be absurd.
Just a few thoughts. Hope my analysis was not mediocre.
I don't know what they do with their sons, but if you have a massage in a nice hotel in Jakarta, they aren't shy about it. (sorry, couldn't help myself to write that)