One thing that worries me if you look at history. Given that someone is willing to leave their entire family and life to embark on a long quest to an unknown l

One thing that worries me if you look at history. Given that someone is willing to leave their entire family and life to embark on a long quest to an unknown land, while many do it for love to get help or knowledge or resources to bring back home to their people, others are doing it because they are looking for a place where they can get away with hate. Even if an alien civilization were 99% peaceful and good, what is the probability that the members of that civilization who would want to venture out, leave their families behind, and come meet us are the good ones or the ones in the other 1%?