Is this really true though? A neutral third party would not supply weapons or have any economic incentive to the outcome of the conflict, which China plainly does have. I'm not saying the US or really any NATO country is in a better position, however saying China is only interested in peace and are a neutral third party is disingenuous.

And as to what Blinken is saying, that's something Ukraine has been saying since the invasion began. Sure it's not his place, however if you interpret it charitably, it could also be construed as supporting the stance of your ally in the face of pressure towards an agreement they don't really want.