It's probably more Cox than Pioneer behind whether those inputs work. Usually when there are features like that on a cable box, it's up to the cable company to determine whether they're to be live or for "future use." If your cable company doesn't want them active, they're not going to be active, and Pioneer really can't help you.
Also, I think when Pioneer restructured due to their recent bankruptcy, they may have gotten out of the cable box business, and what is left is surplus that Cox is putting to use as long as they still work. That's just conjecture, but I wouldn't be surprised. They dropped making plasma screens and other CE items in favor of more profitable car stereos and AV receivers. There may not be anyone left there that knows anything about their cable boxes.
Don't believe everything on the Interwebz! A duck's quack DOES echo!