There are a number of other places that would have the same knee-jerk dismissal based on opposition to China. Also I think China would probably view it as not conducive to its national security to take those kinds of shots at every opportunity (because such a thing has substantial risk of exposing how they got the information) as opposed to, for example, using its intelligence networks to make sure their own bourgeoisie, diplomats, etc. don't get turned into assets.

Also, there's ongoing struggle in America to unredact more of the files, so there's no need to get involved and fuck up the process by turning this into "everyone who wants to unredact the files is a useful idiot for chyna" when more will almost certainly be dredged up without China's involvement.