有关七宗罪中的gratuitous assumption的问题

追命Brian

gratuitous assumption字面翻译是不明白的假设 但他的意思我老是搞不懂 请各位NN指点下小弟 小弟马上就要考了 谢谢
拿个例子吧
“The common notion that workers are generally apathetic about management issues is false, or at least outdated: a recently published survey indicates that 79 percent of the nearly 1,200 workers who responded to survey questionnaires expressed a high level of interest in the topics of corporate restructuring and redesign of benefits programs.”
    gratuitous assumption: It is natural that workers are interested in the topics such as corporate structuring and design of benefits programs. This trend can not be cited to support the author’s allege.
请高手解释下 谢谢