The Diary of Anne Frank has become regarded as an important work of literature all because it tells the truth, with the backdrop of the Nazi era adding a sense of dark imperative. Censoring any of it takes a lot of power away from the work as a whole. Pornographic materials exist to stimulate, whereas Anne Frank wishes only to tell the truth about herself.
No, I don't think that Anne Frank's diary was pornographic, because I think she was just talking about her normal life. There were not photographs or pornography in her diary, so there is no way to say that it was pornographic. Pornography is images more than anything else. Frank was just talking about her life.
Anne Frank's diary was just that: a diary. She wrote it to pass the time and document the things happening in her life. She didn't mean for others to read it and see the graphic nature of what she wrote. It was personal, just for her to write her thoughts and feelings. No pornography, just personal.
As much as the PC police would like you to believe otherwise, life is not sanitary. The reason that Anne Frank's diary is so powerful is because it's raw and real. Once you start trying to sanitize the contents, you start the road down censorship. Readers should be allowed to read the complete uncensored material as it was written. Otherwise you lose the connection to the writer.