> No, seriously, what ongoing action(s) of China “must be stopped” and what actions by whom are likely to succeed without causing more harm than that which would be stopped?

I literally could give some likely possibilities of what they were specifically thinking about from memory, but it's basically a list of major news stories about the PRC from the past several years, which you're welcome to research yourself.

> The win/loss/left-a-mess ratio of the US doesn’t engender positive predictions of future actions especially given how many are in endless overtime. Is it fatalistic to be realistic?

The PRC is a genuinely difficult geopolitical problem. However, you seem to be taking Iraq and Afghanistan as your main precedents for action, when they'd be poor ones even if the US had been far more successful there.