"In and of itself" is a set phrase in English. It is used here to indicate that the thing in question is not a bad thing, though there may be other things that are worse. For example, "The fact that one has a herniated disc is not a bad thing in and of itself, but the cracked spine will be a problem." One could write, "The fact that one has a herniated disc is not a bad thing", but, by writing it this way, the option to discuss other problems is not available.
I think you misunderstood my question. I understand the meaning of "in and of itself," but I think one could simply write "in itself" and there would be no difference in meaning.