I'm curious, where? I've never been to any part of Asia where drinking orange juice was common.
Other than Tropicana which is available most “orange juice” is Asia is more similar to Sunny Delight —which is not my glass of orange juice.
Presumably OP means freshly squeezed orange juice, which might taste a bit sour. I cannot imagine adding sugar to some sugar-flavored orange water like Sunny Delight. Or maybe it is that bad.
I don't know about the oranges in Asia, but in Brazil they are not bitter at all.
And people only put sugar in it when they are bad/old, and even then it's uncommon.