Hacking is basically a form of theft, and a violation of the property of others. So if there's a candidate who openly admits to hacking i.e. stealing, that's pretty much disqualifying in terms of running for public office. Maybe there are some extenuating circumstances, but for the most part, I think hacking is a crime.
Hacking is a touchy subject because nobody really knows how to handle it. Cyber crimes are hard to punish too because it is completely new territory for the law. But unless you have committed a violent and unforgivable crime then you should not be held back from running for office.
Hacking is a serious crime, but it doesn't neccesarily prevent someone from running for office. The people should be smart enough to decide whether or not a person's crimes should keep them from holding the office that they are running for. That is part of what being a democracy is about.
If the subject of which the hacking is being done on or for happens to be something that the government is trying to hide from the people, I believe it is a service for the greater good. I know it sounds like a sort of vigilantism but sometimes that could be just what we need. Lies being fed to you by your government should be a big red flag that they do not have your best interests in mind even if they say they do.