One thing has nothing to do with the other. Timestamps are intended to simply record what the time is in a given place - not to telegraph expectations about loc

One thing has nothing to do with the other. Timestamps are intended to simply record what the time is in a given place - not to telegraph expectations about local business hours. China has one official time zone that covers five geographical time zones. Tell me, exactly how does saying "It's 6PM in China" tell me anything useful about the local library? You have to go to a local website and find out what time "in that part of China" the library is open. The timezone was never intended to express that.