Why hasn't China cut ties with the US or Japan, why did China build diplomatic relations with them in the first place back in 1972? Why does China not have diplomatic relations with countries that "recognize" Taiwan province as an "independent country", but still maintain ties with a genocidal Israel? Why hasn't Russia cut ties with the US?
What does it mean to cut ties, for all official communication between two governments to stop? For all trade between two countries to stop? Cutting ties will not stop Israel from continuing its war crimes. I think China wants to be more of a mediator between Israel and Palestine as it supports a two-state solution, so cutting ties with any side will work against that.
According to this Wikipedia page:
As of 28 May 2024, 145 of the 193 United Nations (UN) member states officially recognize the State of Palestine (Israel is recognized by 165).