I think you are as naive as I am or perhaps more. The American People knew all about Bill Ayers and did not care. He could be on the cover with Obama and it would not have bothered the American voters (at least 54 percent). Now why on Earth would Obama put Ayers on his cover if he was only the ghostwriter?
The American left doesn't think communism was all that bad. They are delusional about this, but live in a dream world about a lot of things.