Yes, it is the case in China for US-bound flights and is quite purposeful. While the US relaxed its post 9-11 rules on allowing liquids purchased past security to be boarded, China decided not to roll back the restriction. I'm sure it's because it's easier to have a clearly-defined, though severe, rule that the staff can uniformly apply to everyone, rather than get into endless arguments with passengers and have to make judgment calls case-by-case a thousand+ times per day on which liquids originated airside and which didn't. As if the gate secondary staff did not have full trust that the primary security screening would catch everything.

China is also ultra-sensitive and paranoid that any explosive might slip through on a US carrier or US-bound flight, maybe more so than with most other countries.