What an ignorant comment.
I recall a colleague telling me about a particularly poor country in Africa where he worked.
He said the people were wonderful and friendly.
They would smile and say thankyou when they robbed you, and would only stab you if you put up a fight.
The friendliness of a people has nothing to do with how safe a country is. What an epically clueless comment. By definition, acts of aggression and violence are perpetrated by the unfriendly minority. What matters is how wide spread the problem is, what protection you get, and how much they are discouraged from their actions.
There are places where local thugs won't touch tourists because if they do the local police will hunt them down and beat the shit out of them. Its the places where the police and government don't give a shit that you have the problem.
Iran is particularly dangerous because you have the government and religious leaders actively encouraging people to hate you. Most people won't, most people don't really care, but it is the minority who create the problems.