Let me take your thoughtful comment a little farther. Reading fiction and poetry should provide pleasure. Perhaps the question is what kind of pleasure is provided by a given story, which implies the kind of reading suited to that story.
I'll use some non-sf examples first -- stories that almost everyone may have read.
Sir Arthur Conan Doyle's Sherlock Holmes atmospheric, suspenseful story "The Speckled Band" has provided me with pleasure every time I have read it, and that's perhaps a dozen times. But the story seems to provide only the pleasure of escape reading. This implies relatively casual reading, although the mind may be pleasantly engaged with the story's puzzle. If I read the story more alertly, several serious flaws appear. Surely the central idea, of the trained snake that crawls through a ventilator grate, down a dummy bell pull, onto a bed bolted to the floor of an adjoining room, there to bite fatally a sleeping womna, and then to crawl back the way it came -- is preposterous. I may enjoy the sense of my own cleverness in seeing through the story's weakness, but that's not a specifically literary pleasure. The same observations would apply to Connell's "The Most Dangerous Game," etc.
Now let's take Nathaniel Hawthorne's "Rappaccini's Daughter." This story can be read as an escape story. You have a sinister old man, a weird garden, a beautiful femme fatale, a legendary setting -- there's much that should have invited the brush of a Pre-Raphaelite painter. If you read the story casually, though, you may feel that the pace is too slow. Some readers will want Beatrice, the young woman whose touch causes pain or death, to amp up her allure because they like to fantasize about vampire-type women, etc. But if you read the story alertly, it has much to offer beyond escape. It deals with perennial human concerns and there's genuine wisdom here, so that the story offers what could be called interpretation.
The escape / interpretation distinction is that of Laurence Perrine. Note: Perrine recommended that we think in terms of a spectrum, with escape at one end and interpretation at the other. Any given story may then provide pleasure, but is the element of escape predominant or does the story invite, or even require, the disciplined attention that interpretive fiction justifies and rewards?
The question then may be: does a given sf story offer nothing but escape, or does it offer genuine insight, engaging us deeply with perennial human concerns -- or, likely enough, the story should be placed somewhere other than at the extremes along a continuum or spectrum of literature?
Speckled Band
O----X------------------------------------------------------------O
Escape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interpretation
Rappaccini's Daughter
O-----------------------------------------------------X-----------O
Escape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interpretation
One can have interesting inner debates or discussions about where to place the mark for a given story. The good thing is that this kind of thinking gets us back into the story.
My own experience suggests that much sf does tend to the escape end of the spectrum.
A related topic is: Supposing the story seems intended to elicit thoughtful reading, does it, in fact, deserve that? Or is it pretentious, i.e. making an implied claim for thoughtful reading that it doesn't deserve?
I have recently reread Rider Haggard's Victorian yarn She. The long-lived, beautiful Ayesha speaks for many pages about Life, etc. You can see that Haggard wants to suggest the insight of a quasi-immortal being who has lived for some 2000 lonely years, pondering the meaning of things. Unfortunately Haggard was not up to the task. One has to take the intention for the deed,* that's for sure. As escape literature, his yarn is a great success. More, it really does partake of myth, but in myth the meaning is in the imagery (including the figures of the story -- one hardly wants to call them characters) and actions. Ovid doesn't attempt to suggest the wisdom of Artemis/Diana by having her dispense thousands of words of her thoughts.
So would it now be appropriate for everyone to offer suggestions about sf and fantasy stories in which the escape element predominates, and of other stories that invite, even require, alert, attentive reading in order that we shall be rewarded with insight into perennial human concerns? But let's all be careful not to be fooled the way Haggard may have fooled some of his readers and himself! A story that seems intended to provide nothing but escape may thus be "better" in a way than a story that seems intended to provide insight but is just badly written, with the "insight" content not integrated into the story, or the insight content seeming fallacious, etc., etc.
*I don't mean that one takes the intention for the deed in assessing the merit of the book. I mean that one "plays along" with Haggard. Haggard meant Ayesha to sound wise; very well, let's continue reading the story, pretending that what she is saying is wise.
One could argue that Haggard achieves something subtle here: his Ayesha has had 2000 years to think about life, and yet this is all that she has come up with -- so Haggard must have intended us to infer that he thinks that, human nature being what it is, it wouldn't matter if we had 2000 years to mull things over, we'd still be stuck with our vanity, etc. and would not necessarily become wise. I think that may well be true; unfortunately, I don't think Haggard intends his readers to take Ayesha's talk (of which there is much) thus ironically. To be sure, he means us to see her as still wrung by her passions and tormented by love for her lost Kallikrates, but I think he did intend her also to be a sage.
On might discuss characters in fantasy and sf who really are convincing as sages. Gandalf in LOTR convinces me. Mr. Raven, in MacDonald's Lilith, is wonderful! Offhand I'm not thinking of any examples in sf.