Marco.org

Dieter Bohn at The Verge reports that the Fire has a system-level component that intercepts and redirects all requests to market.android.com:

That method means that even if you disable Amazon’s Silk cloud proxy server or go through the extra step to install a third party browser like Dolphin, this little file will redirect your requests to Amazon’s own store.

The Kindle Fire’s top priority is selling Amazon’s content. Everything else is secondary.