[sanityinc]

At least xmonad starts with an "x". Alternatives like "ratpoison", "enlightenment", "metacity" or "sawfish" have names which are arguably even less meaningful to end users.

In my view there's really no tension between naming things after implementation details and giving them abstract unrelated names -- all that really matters in the long term is that a name is memorable, and memorable names can and do come from either approach.