Birds of a feather flock together. Say you're a business owner, would you hire a sicko perv to be your manager? Would a sicko perv be one of your oldest and dearest friends? Would you attend events with him and eat at his house?
There's a lot of confusion about John and Tony Podesta. If you're a boss, you certainly should check out your employees, but if they turn out to have crazy relatives, you may not want to fire your underlings for having the wrong siblings. Plus, when people have things they want to hide, they can usually hide them pretty well.