Okay, so I guess we're clear that your comment is not about the case being discussed.
But first let's clear up a point. This is not about not holding the guy doing the shooting responsible for what he did. He is still responsible for his actions.
But often other people can share legal responsibility. That's the way it's been for a long time. So, for example, if a bartender serves alcohol to someone obviously intoxicated in some States the bar can be also be held liable for the damages caused if the customer then gets into an accident. The drunk guy is still liable as well of course, but someone else (the bar) shares in the responsibility because it did not act in a manner consistent with the standard of care expect of businesses that sell drinks in light of the risks of drunk drivers causing accidents. You might not think that's right, but that's the way it is in a number of States.
This isn't quite the same thing. The plaintiff's theory of liability is somewhat different. And this ruling doesn't hold Armslist liable. It merely allow the lawsuit to continue.
But by not reading the case and trying to understand how the court reached its decision is a missed opportunity to try to learn how things actually do work in real life rather than relying on your "NJ opinion" about "the way our laws are suppose to work." Things in the real world are the way they are, not necessarily how you think they're supposed to be.
You also probably missed out on reading
the article in the Technology & Marketing Law Blog linked to by Arizona Mike in post 18. That's too bad because that article offers a principled critique of the decision here and again can be helpful to persons who are interested in actually learning something about how things work in real life.