Hvorfor er det "hvorfor"? Doesn't this mean "wherefor?". -for endings are used for location (utenfor, nedenfor).
You are completely right! Which is a good thing, because "wherefore" is actually an acceptable way to say "why" in English! https://en.wiktionary.org/wiki/wherefore
The more you know
Harald, good point. Sometimes we will say "what for?" as in "to what purpose?". Gotta admit that "WHY?" is much easier. Did you want to offer any insight to "whereas" which is often seen in contracts or resolution framework? 31Mar18