That's not really the point though; Mark has made _zero_ posts on his Google+ account and updates his real Facebook account fairly frequently. One is a freshly-updated, lively social search result and the other is almost worthless.
This is equivalent of saying Google is giving Google+ pages preferential treatment unless a Google+ page explicitly states it does not want such a treatment. I won't say that is fair.
For the record, Mark Zuckerberg can make his profile not visible to search engines if he so wanted: http://support.google.com/plus/bin/answer.py?hl=en&answe...