Because...
This is why you see outage notices like:
Things broke. We fixed it. Carry on.
And security bulletins like:
This patch fixes a remote access vulnerability in Windows.
Which tends to inflame our detail-oriented sysadminny sensibilities. Our whole world is complexity, we like to see it. Lets us know that things are normal.
I agree that providing too much information to users only causes confusion. However, the information should still be available for admins, developers, and users who do want to learn more about what's going on.