This is not about ability. This is about trust. They say the data is anonymous which means they are obligated to disregard the IP address and to not log it anywhere.
Sure it is. That's exactly what the following statement means: "Apple cannot identify the source of this data". How can you interpret that as anything else but their ability of identifying the source?
The statement is obviously not true; if they were forced to, by a government agency for example, to track the location information from a user from that point on they COULD; saying they can't is wrong IMHO.
The correct thing to say here is that they can, but they don't, unless forced to. But I guess that isn't the message Apple wants to communicate.
They have access to it sure. But they have access to it through a lot of other methods. In fact they even have your credit card information. You gave to it them :)