Actually, they don't ignore the social issues, at least not in the lore (before everything got folded into the Academy lore quests). The novel Needs of the Many, plus the STO lore available, note that The Doctor (and the Soong Foundation I believe) went to court after Starfleet tried to take away his mobile emitter, with the case evolving into a class-action suit in favor of all sentient synthetics (to use a Mass Effect term).
The court ruled in favor, and worked with scientists to come up with a bunch of tests to determine when a hologram or android has become sentient (and thus deserving rights).
As for Data and positronic androids, true, Data is unique (at least as far a "Soong-type" androids are concerned), but he came back when his memories implanted in B-4 were retriggered. Needs of the Many has a whole chapter dedicated to that event.
Books are not canon. Besides, that isn't the social issue I was talking about.
I meant the ramifications of sentient holograms coming into general use (as opposed to one-of situations like Data).
It is especially an issue in an environment where eugenics are outlawed. How can artificial or augmented humans be illegal to create, but artificial designer holograms or androids be perfectly legal to create?
And what are the ramifications of entering significant numbers of such beings into the labor force? How are they powered? If they use standard dilithium based power sources, what does that do with respect to the dilithium supply, which is always implied to be at least somewhat limited?
There are scads of science fiction works exploring the pitfalls of such technology becoming widespread and a reason why Data was a one-of in canon (well, two-of including Lore).
There are other issues for writers too... I wouldn't be completely surprised if the whole Data/ B-4 thing was to allow the possibility for Data to end up more 'mortal', so that if they did do another series further in the future, they wouldn't have to explain either the lack of Data or why he no longer looks like Brent Spiner. And if they didn't have that in their minds, they should have.