I don't think being part of an adsense sharing programe would normally allow you access to their analytics. If it's a successful site the sort of data that's in there would be a goldmine to their competition. Or to anyone who wasn't their competition now, but had the thought to start up a rival site.
Snipsly.com allows its members to access analytics for data relating to their own articles. So does Hubpages. It seems easy to implement. I can't see why all article publishing sites don't do the same. I view my stats for my articles on snipsly.com in the same place as my websites and blogs and it does help deciding what is profitable.
It's not a facility that most article sites have - generally they have their own much simpler stats - most article sites simply tell you how many hits you had and that's it.
One particular site has been promising better statistics but has not delivered them. I find this sus. What I was trying to get to (with the help of DP members who know about this type of thing) was what they have to hide and how easy it is to implement analytics in the style of snipsly.com. I know of sites who have simpler stats but that really has nothing to do with the thread post.
Paranoid much? I doubt that it's because they've got something to hide. They just havn't got round to implementing it. I have 101 things I havn't got round to on sites I run. Some of them are really good things. I'm not hiding anything, just don't have enough hours in the day. If you ever find a webmaster who has, he/she is doing it wrong.