I'm not sure if categorization has to create that...I think it happens more when that categorization is based on a power dynamic/hierarchy. I suppose there can be an "other" without that, but that's not the same as us vs them.

In my view it's the worst part because it's what makes all criticism ineffectual. Thereby the criticism itself is part of the process of making itself ineffectual. It's really quite sad.

I have no idea who David Broder is, but I s'pose my opinion is similar to that. For me, though, it's not a matter so much of us vs. them language, though, as us vs. them social positions and identities. Whether the criticism is emotional or level-headed, so long as it's laying blame, or even just so long as it's creating social difference, it's doing the same work, and that difference, in a hierarchical structure, just pushes you further down.