http://www.techwench.com/why-google-limits-access-to-facebook-through-gmail/

The relationship between Google and Facebook is complicated but it has never been so tense following Google’s decision to prevent Facebook users from obtaining direct access from their Gmail account. It illustrates a growing rivalry between the two major Internet companies. The world’s number one Internet search engine no longer allows automatic email imports to Facebook friend list, unless there is a reciprocal flow of information.