As the intelligence of a species goes high, they tend to be more obedient. They usually live in groups and have some kind of social life. They have rules among them and a leader or boss to rule them. For example, look at gorillas and wolves.
At the peak of this subject are humans. They are the most intelligent species on earth. They have a complicated social life and numerous rules among them. They live in such large groups that millions of them can be ruled by a single one.
Having a leader to guide them for good is absolutely fine. But when millions of humans obey a wrong leader that do no good for them is a strange thing. They may abuse the power for their own sake and continue to be in power for years even though most of people now that his is unfit for that position. Only few of them dare to protest and that illegitimate person uses others to silence them.
Many wars were prevented from happening and tens of millions of lives had been saved if humans had not been that obedient.