belief in its own rectitude at a tragic and brutal cost

[kazuhiko fudaba]

In the article of VOA: With Trump-Kim Summit Over, What Now?, there is a sentence as follows.

What astute analysts of the North have realized over the decades is the Kim family dynasty's unwavering belief in its own rectitude
at a tragic and brutal cost to its own people.

Question) Please explain me the bold part.

Thank you.

Kazu Fudaba

 

[Copyright]

Do you know what "rectitude" is?

 

[kazuhiko fudaba]

They believe it is right to pay for tragic and brutal activities to its own people. This is what I've paraphrased the bold part.
Consulting the dictionary, I think the word 'rectitude' means rightness.

Thank you.

 

[Copyright]

The Kim family's belief that they are always right comes at great cost to the Korean people; i.e., the Korean people suffer because of this Kim family belief.