Comment by WorldMaker

The etymology of the term is from Latin (for "hidden grotto"), and English inherited denotations (Dictionary meanings) both from German font usage and from French. I was pointing out the connotation (colloquial meaning) in English of "ugly" simply that it shows evidence for a long standing cultural bias. Enough of a long standing cultural bias that people may call them "ugly" simply out of "cultural habit" without examining where that bias came from or why they feel that way.

I also subjectively think many of the grotesque fonts are quite pretty, and I like Comic Sans too, but if you are asking why people think they are "ugly", one of the reasons is "subconscious cultural bias" and the "language lesson" was pointing out deep evidence of that (at least in English speaking cultures).