You have a very low opinion of liberals. The idea that a liberal Obama-fan would lie like a rug to fundamentally harm Obama, in a misguided/non-credible* effort to sell books, places liberal morals in the toilet.
But perhaps you have insider info on this subject?
*Andersen’s target audience was/is liberals. Conservatives, with a few negligible exceptions, don’t buy Obama bios written by Obama-fans. Liberals, otoh, don’t buy Obama bios to see their hero’s honesty, credibility, integrity, work ethic and purported literary talent humiliatingly demolished. The argument that Andersen trashed Obama to sell books doesn’t hold water—not even toilet water.