Why did Obama continue to communicate with Ayers?

A question a responsible media would be asking.

"I confess I haven't followed the Ayers matter — except for one key and persistently bothersome detail — the continued communications following 9/11. Relying on the unimpeachable New York Times, I learned two fact: (one), Bill Ayers, in 2001 said that he felt that he had not done enough bombing and could not rule out the possibility that he might have done it all over again; (two) for the next four years (until 2005 when Obama reached the Senate), Obama communicated with Ayers by phone and email (e.g.: "[they] have not spoken by phone or exchanged e-mail messages since Mr. Obama began serving in the United States Senate in January 2005." NY Times)

So why would anyone in a post-9/11 climate continue to communicate with such a loathsome character for four years, when it was common knowledge that Ayers had approved (no, was proud) of his past terrorist tactics of bombing buildings?

Obama may plead the 'I was only 8 years old' line about Ayers' bombing career, or the 'I bumped into him on the street once or twice' story, or the narrative of 'I served with him on a board with some Republicans'. But really, the continued association by phone and email with a proud, creepy Ayers is simply mystifiying and has been rarely raised and never explained."