Reigned by the same family

In a third world country, they call it "dictatorship" or "monarchy" in the West, when some leader can pass down the power to his spouse or his children.
Last election in the US, they tried to sell that as a positive accomplishment when a certain former leader's wife made it to the presidential position, and they presented it in the public as "ain't no alternative", even going on with citing her biological sex as the perfect reason why she should be there.
Now tell the fuck what is so different about that mindset than the one from the third world country?
What is so different about people from the same dynasties offering themselves as leaders for the election over and over again, presenting themselves as a holy gift of God that needs to be chosen?
Like politics got nobody else to offer who's also talented for the job?
And, at all, what makes the people to elect those think, because their spouse, their father/mother or anybody else from the family was a good politician, that they're good politicians too?
What is the difference in here what distinguishes one aristocracy from the other and gives it the positive moral attribute?