Let's take a look at what's being referenced by the stimulus.
What are the views of "certain notables?" They "called for the enslavement of of unemployed laborers who roamed the British countryside - an acceptance of coerced labor." In other words, some people did in fact support slavery at the time, if in a different form than what existed.
In line 31, the passage states that Etlis is "eschewing (rejecting) Drescher's idealization of of traditions of British liberty." The fact that "certain notables" supported coerced labor in some form indicates that British traditions of liberty were not so strong, after all.
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