If you ask a science fiction writer about the future, about what they think is going to be the next big cultural or technological breakthrough they all say something like, "science fiction is about the present, dontchaknow the future just makes it easier to talk about the present without getting in trouble."

While this is true, it always sounds (to me) like an attempt to force the "mainstream" to take science fiction more seriously. It's harder to be dismissive of people who define their work in terms to which you're sympathetic.

I'm of the opinion that when disciplines and genres get really defensive and insistent in making arguments for their own relevancy, it usually reflects some significant doubt.

Science fiction reflects the present, comments on the present, this is quite true (and key to the genre), but it's also about the future. And that's ok. Thinking about the future, about possibilities, more than the opportunity for critique is (part) of what makes this genre so powerful and culturally useful. To deny this, is to draw attention away from imaginations of the future sacrifice distracts what probably makes the genre so important.