I'm curious as to why extreme examples are "weak" in the context of evaluating a framework to evaluate hyperlinks. Whatever policy the courts put in place, they have to handle both extreme and non-extreme situations.

Following your line of reasoning, we'd accept that building a website with the sole intention of linking to kiddie porn would be OK - because the author of those links has no control over what's on the other side.

As with most discussions like these, the trick is in how to draw the line, how to strike the balance.