The Klingons were on the planet for the same (unofficial) reason as Starfleet. They were looking for signs of the Shedai. The Tholians on the other hand were looking to prevent people from discovering or using the Shedai tech. Without the Shedai presence the danger to the colonists from either of these forces was much, much less. By not telling them about the Shedai Starfleet was making them a target for all three races.
Using my Vegas analogy, it's like telling people that your hotel is undergoing major renovations (Klingons & Tholians) when the real danger is that you have a very good idea it's going to be imploded (Shedai).
reyes get's to grow old in his bed with the woman he loves at his side and yet he allowed hundred of people to go into a situation that he knew was much more dangerous than they thought it was. He witheld information that could have led to them changing their minds. Why should Nogura be condemned for his actions when Reyes isn't? Wrong is wrong.
Don't get me wrong. I like that this version of Trek is showing some people to be nasty, petty and all around awful at times. I just like to see justice done. Nogura and Reyes escaped that.