I remember a Star Trek: TOS episode in which Kirk was captured on a primitive planet and the head was asking Kirk to call Enterprise crews so that he could make them gladiators. Kirk also found a Starfleet captain there whose crew was already dead as gladiators.
The head of that primitive planet only had one weapon: The Prime Directive. Somehow, he knew that Starfleet had a rule called Prime Directive which doesn't allow any Starfleet guy to interfere with primitive civilization.
Now, my question is: Is Prime Directive really applicable here when a primitive civilization already knows about Starfleet and its technology? Also, if a primitive civilization is deliberately killing Starfleet officers, isn't it OK for Mankind to crush that civilization? If crushing entire civilization is too much, what was wrong with a special rescue operation?
Also, how important is the Prime Directive over survival? Maybe, Spock's logic was right in Star Trek Into Darkness (assumption: Both timelines have same Prime Directive), but wasn't this a point of survival of entire crew? I don't think Starfleet would have killed them just for that (Star Trek Into Darkness supports this too). Why were captains hesitating even to order abandoning him there or discussing about this special case of Prime Directive to Starfleet?