To be fair, the purpose of HN is to serve YC -- that's why we don't see ads on the site. People have suggested not scribd-ing everything before; I can only assume that the reason this has not yet happened is because the feedback we are providing is more valuable to YC than a few upset readers.
And this may well be the case: When most people have problems accessing a web page one way, they won't tell you directly; instead, they'll try to find another way to access it or give up. By providing only one way to read PDFs on a discussion board, you get access to this otherwise invisible negative feedback.
Yes, but not every idea turns out to be a good one.
Based on the unanimous jeers every time a PDF submission gets autoconverted, scribd appears not to be one of the good ones. Maybe it's time to try something else.
If they're trying to send more traffic to that site, then we're S.O.L.
OTOH, if they're just trying to increase the number of documents in scribd's repository, then a parallel submission process would be the solution.
I.e., keep HN posts pointing to the original pdf, but also auto-submit to scribe, behind the scenes in a separate thread.