No, au contraire, it is you who holds the erroneous opinion that...
a) In a monarchal system there exists the potential of an evil monarch to reign within the system.
b) Next, what follows is that this monarch has the potential to bring down the entire system based upon his evil.
c) Therefore, because of this possibility, it is best to avoid monarchy because of the potential this one individual has in destroying the system.
I answer that...
a) In every system of government, there exists the potential for a superior to act in a way contrary to their given position.
So, OP, do you discredit government in general?
Do you discredit the family because of the potential of the father of being a greedy, drunken gambler?