Controversial piece on where Science Fiction lost its way is available at Ruthless Culture. Broadly, Jonathan McCalmont claims that the genre has abandoned political engagement and become too infused with fantasy elements. Increasingly it is written in an abstract and fantastical manner rather than having any drive to engage with real world problems or potential alternatives to capitalism. He ties this in with the lack of non-white, non-male authors and the opportunities that fantastic science fiction offers for air brushing inconvenient and embarrassing events in the history of the imperialist West.
I would disagree with this characterisation of the state of play. Political meanings can be drawn from even the most abstract or unrealistic text and some of the examples he quotes (especially Iain Banks and China Mieville) make some very obvious political comments in their works. Whether or not they should be more politically assertive as public figures is a different question and does not reflect on the quality of their writing.
Still I won't attempt a detailled rebuttal or commentary here. Read the thought-provoking piece and have a gander at the number of prominent authors who have replied to challenge it!