For a story-id question I believe we can't, by precedent, rule it off-topic. While whether or not a particular work is on-topic or not largely comes down to cases, one of the unique things about story-id questions is that we don't know the applicable work. In general we are very lenient with story-id questions as long as the asker makes a good-faith assertion that they believe the work is on-topic and can point to at least some SFnal trope or detail.
Also, there are obviously a number of written SF works that are quite sexually graphic, some beyond even what would be possible to film. (I'm not recommending reading it, quite the contrary, but if you've read Farmer's Image of the Beast you know what I'm talking about.) These are obviously on-topic, especially those where the space-phlebotinum requires sex to work. If someone were to film those works, they would likely be pornographic, but still definitely on-topic.
Even beyond that, consider that the genre includes works that are basically serial-numbers-filed-off westerns transposed into a "space" milieu. Wooden ships and iron men in space is also an accepted part of the genre, along with space-pirates...
I don't think we can be less accommodating of SFnal transformations of any other base style. In other words if a space-western is on-topic, then space-porn pretty much has to be too.