I think Parler's argument was that Amazon broke their contract with Parler. Amazon does have a legal obligation to uphold their end of the Amazon Terms of Servi

I think Parler's argument was that Amazon broke their contract with Parler. Amazon does have a legal obligation to uphold their end of the Amazon Terms of Service. These terms also are only enforceable through arbitration (a point I disagree strongly with and wish to see done away with). This is an argument that Amazon could have used.