I think the author was not willing (or it did not strike him at all) that the meaning of word 'hacker' could be anything different than what he had in mind.

Once any one does that, the rest of the explanation can be used to support the definition already in mind. The "testing the boundaries..." could have left him with an impression that Zuckerberg is supporting "hacking" because it 'tests the boundaries of what can be done in general'.