You need to understand how HN works. Whenever someone submits a link that was already submitted, the submitted link gets a point.

So the techcrunch article would get more upvotes, as more people would be submitting it, compared to some random slideshare page.

And since the techcrunch article would get more upvotes in a short period of time, it'll end up on the front page quickly, which will in turn get that submission more upvotes.