Nevertheless, if you're a programmer with no particular exposure to that sort of math (which is to say, the overwhelming majority of programmers), saying "this

Nevertheless, if you're a programmer with no particular exposure to that sort of math (which is to say, the overwhelming majority of programmers), saying "this function takes a Monoid" is as useful as saying "this function takes a Foogblort." Saying "this function takes an Appendable" conveys useful information. It's a matter of priorities. If your priority is using the correct mathematical term, you necessarily sacrifice clarity to newcomers. Hence, fewer newcomers. ...of course, not that Haskell as a language has ever strived to attract newcomers!