Hmm. Here, extracted from the comment above, is the basis of my point of view

    I submitted here to HN a link to a PDF which is
    copyrighted.  That has been uploaded to scribd
    without acknowledgement. When I contacted scribd
    to ask them to take it down they said it was the
    responsibility of the copyright owner to make a
    formal request for takedown.

    Who ticked the box? I certainly didn't. Who checked
    that the person ticking the box had any right to do
    so? Scribd certainly didn't.

From those facts I concluded:

    Scribd make no effort to ensure that copyright is
    not breached. There is no traceability.  Their
    "efforts" are ineffective and insufficient.

There was a breach of copyright, and certainly I wasn't contacted. I'm assuming the author wasn't contacted - scribd certainly don't appear to be proactive in contacting the author of everything uploaded.

Someone has uploaded copyrighted material to scribd, and it's still there. Hence I conclude:

    If someone uploads material to scribd in breach of
    copyright, there are no sanctions, there is no
    culpability.

Now, would you care to point out the strawman argument? I would be delighted to learn that a service I have hitherto thought of as the scum of the Earth are, in fact, noble and just.

No, really, I would, and I'm just being selfish. Currently I get very angry thinking about their existence, and if I learned that I was wrong I'd be happier.

Please.

If you can't, then I suggest that when you say:

   ... you seem to have a insider's view into Scribd's
   back end. If not, then you're just bloviating and
   making strawman arguments that don't really stand up.

then your logic is faulty.