The only attack is a single phrase, referring to him as a "sociopathic billionaire". I don't think his status as a billionaire is questioned, so you must object to the use of the one word "sociopathic". Let's check the DSM-IV:

Antisocial personality disorder is characterized by a lack of regard for the moral or legal standards in the local culture. There is a marked inability to get along with others or abide by societal rules. Individuals with this disorder are sometimes called psychopaths or sociopaths.

Well, not exactly clear-cut, but I think a reasonable set of people, perhaps including Thiel, would agree that he has "a lack of regard for the moral or legal standards in the local culture"