In general, the distinction between manipulation and argumentation, is that argumentation attempts to get the reader to see your point of view. That is, if I b

In general, the distinction between manipulation and argumentation, is that argumentation attempts to get the reader to see your point of view. That is, if I believe X for reason Y, then I will say that in my article. Manipulation would be arguing X for whatever reason you think the reader will find convincing. In this case, the criticism was that the Guardian argues against drone strikes (and perhaps this particular war), by using some poor arguments e.g. that drone strikes are especially likely to kill civilians.