It sounds like the problem isn't Valleywag, but whoever is submitting articles from Valleywag (that is, if I'm properly understanding how news.yc works). If people stop submitting them, then the problem will go away right?
We should just make it known that it is not socially acceptable for people to submit worthless articles to our community, no matter what site the articles from come.
If someone submits something from Valleywag, heap scorn upon them! But if someone is voting for it, then someone likes it. Appealing to the lowest common denominator (no offense) is part of democracy.