This guy isn't just "some journalist," he's also a far Left radical activist from Madison, WI. He's been a speaker at Bernie events, and in his interviews he espouses all the typical Left-wing talking points (systemic racism, police brutality, MAGA extremists, etc.).
His published books include: Uprising: How Wisconsin Renewed the Politics of Protest, from Madison to Wall Street and Horsemen of the Trumpocalypse: A Field Guide to the Most Dangerous People in America.
And if you listen to the audio comparisons of this guy speaking it doesn't rule him out.
If he were in his twenties or even his thirties it would be more likely. He’s in his sixties. At that age people are more careful, and less willing to take risks or commit to mad schemes. Even if he were going to riot he’d probably do it for his own side, rather than going to all the trouble of pretending to be someone he wasn’t.
And the activist thing? There are “activists” and there are activists. There are people who just write books in favor of protests and uprisings and people who actually participate in them. There’s some overlap, but people in one group aren’t necessarily in the other.