The same thing that's made china not have an overt military conflict for the past half century: they're not a militaristic, expansionist country.
Uh..
The Philippines, Brunei, Malaysia all disagree..
India disagrees.
Nepal disagrees.
Bhutan disagrees.
I could keep going but my train is almost at my stop. China tries their best to keep their conflicts on the quiet-side to prevent sanctions like the west did to Russia.
"Your evidence is overwhelming, so I will point out what I don't like about one source, ignore all others, and then try to use whataboutism to further bury myself in this hole I've created ."