Before we examine this question you should ask yourself an important question, "Does that change in any way the content of those emails?" No, it does not.

DNC emails reveal a Clinton campaign that’s shady and dishonest, not to mention corrupt. Its secret dealings with Hillary’s opponents—whether Bernie Sanders or Donald Trump—have been distasteful and possibly illegal. To say this is an unflattering portrayal of Team Clinton is like saying the Titanic had issues with ice.

A hacker named Guccifer 2.0 had already claimed credit for the hack a month ago. According to Guccifer, who gave a magazine interview, “i’m a hacker, manager, philosopher, women lover. I also like Gucci! I bring the light to people. I’m a freedom fighter! So u can choose what u like!”.

He again denied being affiliated with Russia, saying, “No because I don’t like Russians and their foreign policy. I hate being attributed to Russia.” He said he hacked the DNC server in summer 2015 and remained inside it until the DNC rebooted its system in June, 2016.

So then the question isn't whether Guccifer 2.0 hacked the DNC. He did.
The question is "Is Guccifer who he says he is?"
To determine that, let's look at the counter-claim - that Putin's men hacked the DNC.

On June 15, 2016, CrowdStrike’s co-founder and CTO Dmitri Alperovich announced in a blog post that two Russian hacker groups were responsible for the DNC breach: Cozy Bear and Fancy Bear; and that both hacker groups worked for competing Russian intelligence services.
Other cybersecurity companies including FireEye, Kaspersky Lab, ESET, TrendMicro, Microsoft, iSight Partners, and AlienLab have made similar claims of attribution to the Russian government. The question that this article seeks to answer is, are those claims grounded in evidence or guesswork?
I chose to look at Fancy Bear (APT28 in FireEye’s ecosystem). The most comprehensive report on that threat actor was written by FireEye and released last October, 2014 so I started with that. To my surprise, the report’s authors declared that they deliberately excluded evidence that didn’t support their judgment that the Russian government was responsible for APT28’s activities:

“APT28 has targeted a variety of organizations that fall outside of the three themes we highlighted above. However, we are not profiling all of APT28’s targets with the same detail because they are not particularly indicative of a specific sponsor’s interests.” (emphasis added)

That is the very definition of confirmation bias.

Democratic allies are in danger of looking like crazy people.
Jeff Stein at Newsweek asks “Does Donald Trump have a subversive partnership with Vladimir Putin’s propaganda machine?”

Jeffrey Goldberg claims "The Republican nominee for president, Donald J. Trump, has chosen this week to unmask himself as a de facto agent of Russian President Vladimir Putin, a KGB-trained dictator who seeks to rebuild the Soviet empire by undermining the free nations of Europe, marginalizing NATO, and ending America’s reign as the world’s sole superpower.”

The Daily Beast says “Trump Invites Putin to Invade Melania’s Home Town.”

The Observer says "Wikileaks has been an obvious Kremlin front for years."

Hillary has already likened Putin to Hitler.

Consider how Putin has almost supernatural powers to influence events around the globe in his favor.
Brexit. Jeremy Corbyn. Hungary’s Victor Orban. Europe's Far Right. Europe's Far Left.

This is some seriously bizarre shit! It's beyond the pale. Or as the NY Times puts it:

It was a remarkable moment: Even at the height of the Cold War, it was hard to find a presidential campaign willing to charge that its rival was essentially secretly doing the bidding of a key American adversary.

In many ways this is McCarthyist, but without communism.

The FBI is investigating now, and I believe that they will be a lot more cautious about throwing around accusations that can't be proven.
It's long past time the Democrats get a grip on reality before they wind up as laughing stocks.

“The entire premise of the piece relies on the paranoid assumption that Putin wants to "destroy the West": ‘Vladimir Putin has a plan for destroying the West – and that plan looks a lot like Donald Trump.’
“Wait, what? Putin may want to undermine the West. He may want to curb the expansion of NATO, but destroy it? Is he Magneto? This is the type of unhinged, over-the-top language that goes unchallenged when discussing the US favorite Eastern menace.”