I believe the point is that while your personal beliefs may lie at any point in some high-dimensional space, if you're getting involved in politics in some anonymous way you should throw all your support behind the single "best" group, even if, like in two-party politics, that means supporting a group you have significant differences with. Non-anonymity (nonymity) changes things, leading to behavior like lobbying multiple parties.

I don't really find it that disturbing, but it does get a little weird when you remember how bad humans are at separating acts from mental states.