There is no way for WikiLeaks to peruse such a large amount of data and determine which information may be harmful or useful...that's the problem with stolen information...there's no way of telling if it's real, fabricated, fictional, useful, or harmful. It's just a guess.
Every government, business, and for that matter every individual person bargains or uses leverage to improve their overall security and prosperity. That's the way it is, and it may not always seem fair or nice.
Just because some douche-bag has gained access to stolen information doesn't mean it's "valuable journalism" to expose it to the world. In fact, exposing various bargains that governments have made can and will seriously undermine that government's international effectiveness at the least and may result in unnecessary deaths or war at worst.