Absolutely. The US allows to to gain control via a democratic system. Flawed like all systems but still democratic. If you can gain power thru that system then you are the legitimate government.

North Korea is thru violence and forces that they maintain power. If you have the means to take control by their rules, then why is that less legitimate and unacceptable by many people? Is there a reason you think only Kim Jong Un alone should be able to use force to hold power?