Re: Kirk and the Prime Directive.
You can only really judge Kirk's action based on the PD as it existed in that era, comparrisons with the PD as it stood in Picard's era are unfair.
After all lmany laws they evolve over time, new cavets are added due to unforseen circumstances having arisen and being resolved. So what was within the law in 2267 might not be within the law in 2367. Training during the Academy days would have reflected this change within in Starfleet and as such they would have been taught what was within the rules and what wasn't.
On the continent of wild endeavour in the mountains of solace and solitude there stood the citadel of the time lords, the oldest and most mighty race in the universe looking down on the galaxies below sworn never to interfere only to watch.