Here's why -
Ellsberg and Snowden are Americans, who released classified information about what our government was doing, information which both men had legal access to. They of course violated the law, and the terms of their employment, by releasing this information, and we can debate whether these violations were warranted by the benefits of the releases to America and by extension the world. In my view, and the view of many others, Ellsberg strengthened our democracy by his actions, by showing the deception on which our instigation of the Vietnam War was based. The benefits of Snowden's release of classified information are less clear, but I'd argue that they still fall on the side of benefitting our democracy, by providing inside information on how we conduct our foreign policy.
But note that in neither case was a break-in involved into someone's private property. Both men had legal access to the information they released. In contrast, the Podesta emails were obtained through hacking, or theft of Podesta's private property. That makes the current Wikileaks release more akin to Nixon's Watergate break-in, than to what Ellsberg did with the Pentagon Papers.
Indeed, just as Watergate was intended to influence the Presidential election of 1972 - get Nixon re-elected - that's exactly what the Wikileaks release is now trying to do with our 2016 election. The release of this information does not provide Americans with information about how our government operates, but rather about how people running campaigns talk about the campaigns. I think Americans are entitled to know about how our government operates, in whatever ways that information is obtained. In contrast, it's certainly interesting to see the inner workings of campaigns, but not via the mechanism of criminally hacking, and not when the hacking is designed not just to inform, but to damage a particular candidate.
And I haven't even addressed the likelihood - near certainty, actually - that the Russians were the ones who did the hacking. If that's the case, then we have an aggressive foreign power attempting to tip the scales of our Presidential election.
But Wikileaks, whether the Russians are behind this or not, has moved from being a force for democracy to a danger to its existence, via their attempt to tamper with our election.
See also The Downfall of Julian Assange