If you're working in Indonesia and your boss is Muslim and you're not, the fastest way to get ahead is to convert.
That plus other one-way traps reinforces Islam as a dominant religion.
This is hyperbole. While Im sure there are businesses where it's true (there are millions of them in Indonesia), it's not common at all, at least in my experience in Java/Sumatera. There are glass ceilings based on ethnicity in some companies, but it's rarely related to religion and more based on cultural cliques.
Technically, the term "Hindu" as defined by the British just meant non-Muslim. In fact, it was the British who popularized the term Hindu in the first place since prior to British influence, there was no such religion, just a broad set of different religions such as Shivaism, Buddhism, Vishnuism and numerous others. In many places such as Assam, Buddha is revered by people who are labeled as Hindu.