Answer:
It sounds like they are saying that it doesn't take much to find messed up people, those people are just there, and that the whole world is messed up.
Step-by-step explanation:
It says "We do not have to visit a madhouse to find disordered minds; our planet is the mental institution of the universe,” so it is really saying that there are disordered minds everywhere, since you don't have to look in one specific place to find messed up people. In the second line, "our planet is the mental institution of the universe.” it sounds like they are saying all of the nutty people are here on this planet.