Of course, we all should absolutely know the etimology of the words we use. In fact, there is nothing more funny than people trying to use words in which they have no clue as to what they mean, or use words that do not even exist. Did someone say "irregardless"?
Etymology is an interesting and fascinating study. Learning the etymology of the words we use can help us learn things about our world and our history that we never would have known otherwise. Etymology also helps us to understand what people from history were saying and to learn the meaning of new words.
Yes, we should know the etimology of the words that we use. It is good to know where the words that we use today come from and what their original meanings were. There are many words that we use today that have meanings that have changed over time. Etimology, thus, is important to understanding how history coincides with language.
Most people have no actual need to know or understand how words came to be. It is an interesting study for those interested in history and linguistics, so it is an area deserving of research, but it isn't important enough for everyone to know. It's more a fun hobby instead of a required high school subject.