Why was Spock really able to resist the mind-sifter? Because its usage, even in a diminished capacity, is violent and the Organians forbade violence on their planet, even if they haven't revealed that yet.
Star Trek: Discovery establishing a war with the Klingons in the mid-2250s further expands on the ease that our typically heavily peaceful heroes are so ready to go to war and ignore the alternatives. Because the start of their careers as Starfleet officers would be influenced by friends across the service being killed in conflict, and these scars still raw for them, they believe that the Klingons preparing for war might as well be a declaration itself.
Also, Chancellor L'Rell was all for maintaining peace with the Federation, with Section 31 working behind the scenes to make sure she stayed in power. With the two powers on the verge of open war once again, something must've gone horribly wrong. Either L'Rell did a 180 on maintaining peace, or her chancellorship didn't last very long.
Given the claim in TNG that women may not sit on the Council (or be Chancellor), it seems likely that L'Rell's administration not only didn't last very long, but it apparently caused longer-term changes within the Empire that were not for the better. The Empire did become more cohesive and unified, but at the price of creeping authoritarianism, chauvinism and eventually open corruption.
The fact that the Federation is initiating contact with what they believe to be a medieval society would seem to be a major violation of the Prime Directive. However, with the Klingons preparing to invade the planet anyway, the natural development of their society will shortly become somewhat academic. Given the combination of that and the threat that would be posed to the Federation by a Klingon base on Organia, this is probably a situation where the Federation considers the PD a non-issue.
