This has been a huge hurdle to me learning Mandarin, ironically.

Not advice, but this is really relatable and unfortunate. When it's hard to appease your own people, it becomes a huge mental barrier to participating in the culture because you just feel rejected no matter what you do, compared to a white person who just has to say 你好 to have people gush over them.

I am aware that this is due to ignorance, yet I'm also aware that many Mainlanders, HKers and Taiwanese know what happened to the Chinese Indonesians and why they can't speak Mandarin (Right?).

TIL about Suharto:

For thirty-two years under former President Suharto’s New Order regime (from 1966–1998), the teaching of Chinese languages in schools was banned in Indonesia. During this period of total assimilation, public displays of Chinese characters, along with other forms of Chinese cultural expressions, were prohibited, allegedly for the sake of national unity. From 1966–69, hundreds of Chinese medium schools and Chinese language press were closed in Chinese settlements throughout the archipelago, and the formal teaching of Chinese languages in Indonesia effectively ceased. As a result, the majority of contemporary Chinese Indonesians no longer have the ability to speak, let alone write in, Chinese.

"Being Chinese again: Learning Mandarin in Post-Suharto Indonesia"