Google is a private company that controls your site's reputation via PageRank -- assuming most of us have a personal site/blog, how is this that much different?
While it's true that Google is in a sense a gatekeeper to people's personal sites, it doesn't claim to be an arbiter of your page's (or your) reputation. Rather, it only claims to be a judge of a page's relevance to the terms a user searches on.
Google absolutely is an arbiter of your page's reputation -- you can see the 0-9 logarithmic scale on Google's Toolbar.
In the early days of Google/PageRank, the SEO world was abuzz with talk of Google's reputation score for each website, and everyone eagerly awaited the Google update to see how the scores changed.
I stand corrected. I still think it's fair to say that the public doesn't view Google as an arbiter of a page's reputation, though as you say they are certainly aiming to be this.
