Perhaps it makes more sense to Chinese eyes, but that looks very odd to me. If Soros tries and fails, he'll lose a lot of money, but that would seem to be no concern of the Chinese government. So if the Chinese authorities had no worries about the outcome it seems like they'd have no reason to try and warn him off; since they are trying to warn him off, it suggests they're worried.

The entire thing sort of comes off as an admission of weakness to me, which I doubt was the intention.

His name alone is enough to scare Chinese bankers who are worried they can't support their currency.