More information leads to better decisions.
Do you trust a used car salesman when you are buying a used car? Probably not, because there is an appreciable probability that he knows something negative about the car that he is not telling you.
Wouldn't it be much better for you if you had access to the salesman's information about the car? Of course it would.
Suppose someone stole his information and made it available to you. It would be good for you - you would strike a better deal. The fact that it is illegal to steal the information and that it is bad for the salesman are two separate issues.
So, in terms of improved decision making, you should be happy about the hacked DNC emails. They provided previously unavailable and important information about the Candidates and Parties. Hence, they made possible better voting decisions. It is unreasonable to believe that the hacked DNC emails adversely effected the election. If they had any effect, it was most likely positive.