Actually, CALEA [2] is a requirement for all US carriers (ISPs/telcos), it's just an extra requirement on anyone peering with a US firm. It's also been around since 1994.
CALEA intercepts are implemented through automated systems, the judge signs a warrant, it's entered into a computer and the wiretaps are done automatically, with the traffic routed to the requesting agency's systems.
In China, they probably noticed that they don't have a legal intercept facility built in, and don't want to spend the time to negotiate with all of the interested parties. So, they put a person on site.
The threat and the outcome is the same. If you don't provide legal intercept, you're going to get locked up.
For an example of what level of access these systems provide, a Greek carrier was hacked through theirs - the hacker(s) turned it on and used it to listen in on the Prime Minister's phone calls[1].
I'm not saying that the Chinese are doing the right thing, just that it's largely equivalent to what happens here.
[1] http://spectrum.ieee.org/telecom/security/the-athens-affair
[2] https://en.wikipedia.org/wiki/Communications_Assistance_for_...