How do you figure? There's no way it could have been Romulans; the whole story occurs during the century-long period of no contact between humans and Romulans. No one even knew what they looked like yet.
Clarification: I was musing that the writers may have confused the characteristics of the two species. (Hence my aside about the House of Duras as a possible in-universe explanation). It does seem like something the Romulans would get up to, rather than the Klingons. (And possibly the Tal Shiar being onto what Section 31 is up to, recruiting the House of Duras into their counter scheme.)