Except that's not what's happening here, unless your claim is they compromised baidu and Qihoo 360 and both don't care to fix it.

baidu and Qihoo 360 are massive companies. Serving the stuff either means they are doing it deliberately (on behalf of the government), or an active MITM is doing it, which given the scale can only mean ISP and ergo (since this is China) government level. The active MITM seems plausible since a) only unencrypted http traffic gets injected (so far), and b) the Chinese government wouldn't want to put the onus on two of their most important internet companies alone.

Baidu could be doing it only to http traffic to make people think it's the government... But I can't imagine that they would want to seem as if they're putting words in the government's mouth.