I think the problem (well, a problem) with Zarek is that he didn't fit into the Cylon plot, not really. Or the Cylons didn't fit into *his* plot, or something. The circumstances under which is politics became relevant again were caused by the Cylons, and the before/after there is interesting, but not how he feels about them. Zarek's issues are other issues; he belonged to that other show, the one Lee was supposed to be on most of the time.

The way they've set him up, there's really no self-evident way he'd feel about the Cylons; he probably doesn't love them, but there's also nothing special about his issues with them. So when suddenly his actions become at least partly dependent on how he feels about the Cylons, like it was re: the collaborator episode, that's where -- IMO -- he becomes hugely inconsistent.

(I'm not quite counting the Quorum thing here. For the moment. I know it's canon, so to reconcile Zarek as a character it has to be taken into account, but I'm still not over believing that that was to a cheap ploy to show us who the 'right side' was and am more reluctant to give it weight as something that really made internal sense.)