If Vietnamese is much like Chinese, I wouldn't be surprised. Chinese speakers don't specify much. They tend to hollar low-context imperatives at each other, and hope that everyone already knows their job. Linguists call this a "high context" language, because if you don't have a good idea of the existing context you won't figure much out.

I suspect it's related to the extremely strict and ridged hierarchies in China, and the extremely flexible and implicit social networks. Your boss doesn't ask you to do a favor. They order you. In contrast, you don't ask your neighbour if you can borrow a cup or sugar, you just take it, and pay back the favor some other time. If they don't let you (and don't have a good reason), you just never talk to them again (or if that's too severe, silently downgrade your relationship with them).

Funnily, "let" and "make" are the same word in Chinese. i.e. "My mother made me do my homework, then she made me watch TV".