Problem is, I disagree with that wholeheartedly. Putting shackles of reality on fiction is probably one of the most creatively inhibiting things you can do.
Asimov's books, for example, fly way outside the realm of physics in some respects, and are incredibly out-dated in others (since the were written circa 1950's). Doesn't mean they are not excellent stories.
Not necessarily, putting reality onto fiction or science fiction only forces the author to be creative in different ways.
It really all depends on the audience in any case. Honor Harrington I've heard is rather realistic in terms of warfare, and has a large audience, whereby the same token Star Wars is entirely unrealistic and has a large audience as well or on the extreme spectrum of things, something like Spell Jammer which age of sail ships travelling through space ether via some magic mumbo jumbo was very popular too. (Volition Bravos!!!)
Saying all science fiction should be realistic is forcing ideas onto other people, but that doesn't mean that author who want realistic fiction can't pursue it. I think that's mainly what the webpage is for, giving authors with realistic ideals the tools they need to create science fiction. Or that's how I take it.
The main problem is when you get Star Wars or Freespace fanboys screaming "no it's realistic!". Well no, it's not. Its just a movie or a video game, take it for what it is and enjoy it. Sci-fi universes or even fantasy ones can be as creative as they want as long as they don't break the suspension of disbelief, and that further, they're internally consistent. All in my opinion of course.