Should it be a requirement that when you walk into a grocery store and ask them for a hammer, they give you directions to a hardware store? Should it be a requirement of your local bridge club that they be able to tell you where you can have a good game of five-card stud?
It's nice if they do, and it probably makes you more inclined to come back later, but it certainly should not be a requirement.
It's not the responsibility of the members of one site to know which of the many places out there on the web, or even on the SE network, will accept a question. That's your responsibility. It's actually kind of rude to the other site for me to send a question there unless I am certain that it's suitable (you can find plenty of Meta.SO questions about that; Brad Larson has linked one below).
(As a note, all of the SE sites have associated Meta sites and chat rooms, where you can, if you're so inclined, ask about the suitability of your question prior to posting it.)