The article claims that US State Department was investigating a leak from the US embassy in Iceland. If the government of Iceland (an ally and NATO member) is cooperating with such an investigation, that is unsurprising.
Wikileaks is a medium for whistleblowers, not a "spy agency"!
Regardless of how you describe it, Wikileaks is of interest to people whose job is counterintelligence (i.e. secret-keeping). Suppose you have information you want to keep secret. I prevent you from keeping that information secret. How shall you regard me?