All men are created equal
The opening of the United States Declaration of Independence states as follows:
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty, and the Pursuit of Happiness. That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed;[4]
My point exactly. The statement is only true within the limits of a set of defining terms. Therefore logical arguments can only occur within the limits of those defining terms.
Phil Robertson's statement was made within the limits of a defining term, sin. Logical argument can only occur within the limit of that defining term, sin. Very little of the negative criticism of Phil Robertson's statement has been within the limits of that defining term, therefore the criticism is not logical.