Comment by DaxxDom on Regas - Chapter 82

@DaxxDom they explained earlier that if he just waltzed in and did that, he would lose the support of the people. These same lords are part of a centuries old group that has been manipulating generations of kings from birth. Due to controlling the political sphere of power in the country as well as using the church to manipulate the people's faith, they are held in high regard by much of the citizenry.

Karas, aka the current king, as well as ALL generations of kings before him are known to have inherited not only the dragons powers, but it's cruel and uncaring nature as well. The people revere the power of the dragon, but the reason the Council of the King's Heart was created in the first place was to act as a bridge between the people and their king who couldn't understand the needs and concerns of "mere ants". This isn't to say that he finds humans to be worthless or anything, but in the same way that someone who may own an ant farm can care for them without understanding them emotionally, the dragon kings had trouble communicating with/understanding the people.

So with that in mind, the Council isn't just popular due to their own active actions to maintain the people's adoration, but also due to the nature of why their position was created centuries ago and the callous nature of the dragon. If Karas were to indiscriminately slaughter them without bringing evidence of their crimes to light, he would lose the trust of the people and be king of nothing when it's all over. Sure he could also just run away after his revenge, but that doesn't stop another group of nobles just taking the Council's place and doing the same corrupt things all over again. So the only way forward is to destroy them politically and socially before he does so physically.