The study described in the link only exposed the subject to a single article. The effect might be different for different amounts of exposure.

In my own experience this seems to be the case. When I briefly read politically opposing blogs I find them so obviously stupid that I'm amazed anyone could take the other side seriously, but when I spend a long while doing it I find my views moderating and sometimes even crossing over despite not being convinced by any of their actual arguments, and begin to be embarrassed by figures I normally admire even though most of what I find directed against them are mere pejoratives. Then afterward the effect wears off. I could be unusually easily-led, but I've heard of enough other similar experiences that I doubt it.