Celebrim
Legend
Something I saw around the net a while ago, probably not word for word: "'Soft science fiction' means 'there were things in my Analog story that made me uncomfortable, like women and feelings."
I just read LeGuin's "The Dispossessed" not that long ago, and not surprisingly because LeGuin is a Grand Master and rarely disappoints, one of the best sci fi books I've read in a long time and it's definitely on the Hard end of the science fiction spectrum even though it's mostly about relationships and social sciences. And I don't think there is anyone much that is going to disagree with that. Basically, none of the technology actually employed in the story is implausible even with modern knowledge. LeGuin is interested in speculative situations that are a bit removed from the modern world, but she doesn't need any wish fulfillment technology to achieve her story goals.
One of my favorite authors on the soft end of the spectrum is Robert Silverberg and he's really deeply interested in questions of identity and personhood and what it means to have a self, which are not questions that are easily answered through plausible and known science, so a lot (but not all) of his stories involve implausible mental powers or transcendental experiences or psychic connections that aren't easily explained by science and probably are contrary to known scientific truths. It's not soft because of the topic that Silverberg is approaching but because of the methodology he is using to approach it. And there is a huge obvious difference between the telepathy in something like "Dying Inside" and the psychic witches and wizards that populate Dune and Star Wars and other space opera works that embrace something very much like traditional ego based magical systems and heroic narratives of chosen ones and epic quests. And that's intentional by the author in both cases. Star Wars very consciously is fantasy fairy tale and not science fiction, because among other things it opens up with "Once upon a time, a long time ago..." And again, it's obvious that something like "Tower of Glass" or "Shadrach in the Furnace" are harder than works like "Dying Inside" or "Time of Changes", and if that isn't obvious to you I can explain it.
There is a part of me that just wants to go off on you for even quoting that sort of dismissive hateful opinion that lurks in some quarters. When people characterize something as soft science fiction or as space opera, that's not usually or typically motivated by sexism. Implying that's a common opinion or that it is an underlying ulterior motive for critiques of science fiction is no less sexism and hateful, than everything that I think you are trying to stand against. It's a hateful well poisoning argument that doesn't do anyone any good or increase anyone's understanding.