Just because someone took an English major doesn't mean he/she is completely ignorant of basic laws of physics; in some cases, the futuristic setting is used merely to distance the happenings of the story itself from our present day context, and by making it 'abstract' in that sense, making it accessible to people who might not be so empathetic with a story set in a specific time and place in the current day and age.
"Physics don't change": I'm sure pre-Copernican astronomers felt the same way about their 'science'.
Science fiction as a genre is not characterised solely by the accuracy of its science but the use to which its context is put. A book that is written with exacting care to be true to scientific theory that is devoid of literary merit isn't science fiction; it's a dissertation. And one could arguably say that a fucking moron physicist (no dig at actual science-inclined people here, this is hypothetical) is much better suited to churning out equations and getting his nads irradiated than balancing the delicate processes which go into the creation of a good novel.
What someone who isn't a physicist needs to know about science can easily be had by a couple of days with the relevant texts and/or Wikipedia. I honestly doub tthe same thing can be said for someone who's much more familiar with writing formulae than writing complete sentences.
The most important aspect of science fiction isn't the science; it's the story. Is it moving? Engrossing? Is there drama, suspense, character development? Is it well-written?
As others have pointed out, the examples of Le Guin and her contemporaries demonstrate that good science fiction can be written even with minimal attention being paid to the science and much more focus being given to the quality of the fiction.
After all, who the hell wants to read six pages of arduous, dry explication of exactly how this Superdimensional Starship Enterprise Galactica achieves FTL flight? The most important things are: what's the crew doing, why are they doing it, and how they feel about that.
To address your point about kindergarteners: children probably believed in the potential existence of robots, aliens, and computers to a much greater degree than most of the adult population, fancy-pants science experts included. Before space travel was an actuality, it was a dream. Sure, utilising a gigantic cannon to fire a manned shell at the moon mayn't have been great science, but it made one hell of a good story.
Also, you are a borderline literate imbecile, since it wouldn't be 4chan without completely baseless insults.