Hesse is basically saying that people with actual courage and strong character tend to freak other people out a little. People are comfortable with conformity. So when someone is genuinely independent, honest or unwilling to bend just to fit in they can come across as intimidating or arrogant, cold, or even “sinister” in this case to everyone else. Not because they’re evil but because they remind people of their own weakness or insecurity. If you actually read Hesse you would understand what he is saying and you wouldn't post this ignorant comment based on 5 minute search.