Since they seem to rotate the speaking duties, this may be deliberate policy to offend like this.

Why?

Who knows. Maybe Xi Jinping wants it that way, or collectively enough people in the leadership had enough?

Wonder if this wolf-warrior diplomacy has any negative impact against China?

On that question, I truly believe it is minimal to none.

Obviously, the west will criticize China, and criticize China over anything they want.

If the west criticizes China over wolf-warrior diplomacy, at least they are criticizing a Chinese message, in that sense the Chinese message got out. Normally when the west criticizes China, no Chinese rebuttal is given. In reality, there is a Chinese rebuttal but it is never reported in the Western media, rendering the Chinese voice non-existent.

With the offensiveness and often the vulgarity of wolf-warrior diplomacy and the eagerness of the Western media to report it, here is something at least where the Western criticism has a direct rebuttal, because it is the Chinese message that is being criticized.

Even though I like classical music, the vulgarity is very real for me too. I am just a simple peasant, laughing my ass off.