You are certainly not alone in your thinking; many people feel that rewarding a poorly-framed question with a thoughtful and detailed answer is not only futile, but in fact is actively detrimental to the site because it grants legitimacy to the poor question and encourages other questioners to let fly with whatever idle wondering crosses their mind, instead of putting some effort, consideration, and research into the asking process.
Indeed, some feel that not only do such questions deserve a close vote, but answers to them (generally answers from higher-rep people who "should know better") deserve a downvote.
My recommendation, though, is not to judge the answer on the quality of the question. If the answerer has made sense of a question phrased so poorly that you could not tease meaning out of it, good for them; if you can then understand how they arrived at that understanding, all the better; and if they have given a solid answer to what they think the question is, better still.
Then too, if the answerer had to make some assumptions in order to come up with a potential answer, as long as they have spelled out those assumptions and encouraged the asker to confirm or invalidate them, I see no reason to downvote.
Only if the quality of the answer itself is questionable, due to unstated assumptions, or to addressing an issue that I cannot find in the actual question, or to simply being wrong in some way, would I consider applying a downvote to it.
In either case, our ultimate hope is not that "poor questions get closed and deleted", but that "poor questions get improved and answered". If the "answer" part comes before the "improvement" part occasionally, it may help guide whoever ends up improving the question.