1) There are indeed some racist images in this book. However, racism isn't the central focus of the book, and in context it's the sort of "colonial" racism that permeated early-mid century Americans' worldview.
2) The racist images and poetry could likely be modified to preserve the integrity of the rest of the book for children
3) Dr. Suess would not have wanted to withdraw this book from publication.
4)If we censor this book, and withdraw it from print, people might be left with an incomplete understanding of Dr. Suess's work and how it evolved.