Because conflating Chinese soldiers and the Imperial Japanese Army is in no way ignorant and wildly offensive.
When its a reference, no.
Bethesda was likely referencing the entire "holdout" concept as a whole.
Not necessarily just the Japanese holdouts of WWII (although they are probably the example that people would think of first, they are not the only example).
In any case, why does a reference to the actions of some Japanese soldiers in WWII have to have Japanese soldiers in order for it to not be offensive?