Could you clarify this point a little?

Sure.

The Internet is full of people who seem to have as one of their primary goals to expound their chosen tribe's political affiliation and defend it against all opposition, even in spaces predominantly dedicated to something else.

If LessWrong becomes a place where local norms allow discussion of the nominal rationality of Libertarianism, or Liberalism, or Conservatism, or whatever, and contrasting it with the demonstrable irrationality of other political ideologies, I expect that a subset of those people will devote significant resources to expounding their chosen tribe's political affiliation and defend it against one another, taking care to from time to time intone the magic formulas "it would be rational to" and "that's not rational" to mask, perhaps even from themselves, the reality of what was going on.

I'd find LW a less useful community were that to happen. I suspect I'm not alone.

I though the primary goals of LW include refining and promoting human rationality, and I see no reason why this goal would not apply to politics.

Can you clarify this point a little? I don't see where I'm suggesting that this goal doesn't apply to politics. What I'm saying is I'm skeptical that a public internet group like LW can achieve this goal as applied to politics.