What was the purpose and source of the repeated sentences about Robert Kennedy in Sirhan’s diary?

The book of writings created by Sirhan Sirhan was a type of program process to instill the desired intentions within his mind and to self-reinforce these. This served, as well, to create physical evidence of him being unhinged and exhibiting quite bizarre behavior. So it was, at once, a tool of manipulation and the creation of the patsy himself, through incriminating evidence. This immediately becomes so inflammatory and so obviously pointing to guilt, there is scarcely the need for a trial in the minds of the public and becomes an open-and-shut case, because the meaning and interpretation are inescapable that there was guilty knowledge prior to the event on the part of the accused. And this all but convicted him, in and of itself, at least in public perception.