For decades China's policy has been team territorial integrity (ie borders were set in 1948, and people shouldn't talk about them). Previously this meant supporting the 1967 borders. Their current position is still consistent with this (Israel still occupies the west bank), and has the added bonus of improving relations in the region which China has already invested a good deal in (see belt and road initiative)

Honestly this is one of the more straightforward cases of geopolitics, shit like the Nigerian Civil war however...