Not to comment on Greenwald personally, but how can you (outside of very cynical nihilism) analyze political/social activities and relationships in depth and not be, to some degree, an activist yourself?

Everyone is a political activist, even people just going about their day. The only difference is the degree to which you're honest with yourself and others about it.

Good journalists have to be, it seems.

No. This is the sign of our times. And I might follow you, I might join your club if you're an activist, but I will not read your news site and pay for it if I want news. Activist opinions are free today.