Firstly, there is not one campaign that's existed since 2000 that won't have had atleast a few campaign staffers with embarrassing emails. Secondly, the issue isn't only about the clear co-ordination with a hostile foreign state, it's that rather than abiding by Assange's own claimed values, he kept the data private and then leaked it over a political campaign to try and cause political damage. That's nothing to do with data being free, that's a political campaign by a foreign power.