I think that you're pushing too hard to denigrate the editorial. Yes, it does not present the whole truth. But then, NOTHING ever presents the full truth. All discussions of anything so complex as politics are necessarily biased, because it is impossible to shed one's own upbringing in interpreting events.
I think that a better metric is the good faith represented in the piece. I have no problem with somebody presenting their opinion, so long as they acknowledge that they are presenting an opinion. The original post struck me as being presented in good faith.
If we apply your criterion, then everything is propaganda.