Anchor: Not only does the word itself sound more fluid, but I also think the connotation it has is more appropriate to the meaning Slate intends.
Entailed: There are words that are similar, but some are more contextually appropriate.
Contradiction: The word in context is the most appropriate one, there are no alternatives.
Contradiction: The flagbearers were the ones flanking the armed guards.
Contradiction: A child is bowling.
Contradiction: You can't exchange the foreign currency.
Contradiction: I have a difficult problem.