Sentence:  Because he spoke openly with what Channing had prophesied someone might - with daring hyperbole - Parker vindicated Channing 's further prophecy that he who committed this infraction of taste would promptly discover how little mercy liberals were disposed to allow to libertarians who <WSD>appeared</WSD> to them libertines . 
Meaning of the word marked with <WSD> tags:  give a certain impression or have a certain outward aspect