Yeah it's an alternate Spock from alternate Prime - we'll call this one the Prime universe where Harry Kim died.
If you're referring to the events of "Deadlock," that wasn't a parallel timeline, it was a physical duplication of the ship -- basically a shipwide "Enemy Within"/"Second Chances" kind of deal, except that the duplicates were "out of phase" and occupying the same physical space as the originals.
I saw a documentary about Trek's origins and how Roddenberry wanted Trek science to be rooted in reality. I bet lines like that have him orbiting in his grave!
It's hardly as if previous Trek series were devoid of bad science. An energy barrier around the rim of the galaxy is completely ridiculous. The telepathic and telekinetic powers, incorporeal consciousnesses, and mind switches/possessions that we saw routinely displayed in TOS are pure fantasy. The recurring trope of starships falling out of orbit when their power goes out is ridiculous (what, did they think the Moon has engines?). The idea of alien planets spontaneously evolving exact duplicates of Earth cultures -- and even explicitly speaking English, as in "Bread and Circuses" -- is complete nonsense, a production convenience with no possible justification in credible science.
And many of those are from episodes that Roddenberry himself wrote. So while he may have aspired to credibility to a certain extent, he wasn't that much better at it than his successors. At least, he didn't hesitate to set aside credibility for the sake of storytelling and drama -- which is what you're supposed
to do. The first priority in fiction is what the story needs. If scientific accuracy helps the story, you use it, but if it impedes the story, you set it aside. Roddenberry understood that. And so does Abrams. Roberto Orci and Alex Kurtzman are actually among the more science-savvy writer/producers in the industry today, and from what I've gathered, their original script for the '09 film had better science than what we ended up with. But Abrams is the director and he makes the final call on story decisions, and he evidently decided that setting aside scientific accuracy in some respects served the dramatic needs of the story better.