To the people who insist that Red John is some gorgeous lady's man and that the women who are his accomplices are besotted with him in some sexual manner - therefore RJ must be incredibly charming and sexy ...

Remember that RJ is a mentalist who uses hypnosis. He can manipulate the minds of (for example) a Lorelei Martins through hypnosis etc. RJ may as well look like Smith, Haffner, Partridge ... Bosco or Laroche for that matter. The look is not relevant when you can use hypnosis.