Killjoys they may have been, but I see no evidence they thought the writer(s) of Esther had dirty minds. I think all things considered, they probably considered the storytelling techniques reflected more sophistication that that: subtlety, wit, irony, social commentary, innuendo, double entendre, etc. and not vulgar, crude, explicit or base jokes generally considered "dirty," and not even coming close to what Nephi called "much rudeness." Plus these were social norms not generally considered shocking at the time.