It's not precluded in sociology, you do that in sociology, too. But most sociologists don't do that. They study why things are the way they are. Okay, that's fine. That has to be done.
Political scientists do that, too.
But my preference was to study things as they are, trying to understand why it is that they are the way they are as a step toward understanding how they might be changed. Within political science, you chose international relations. No, it isn't obvious. Because the same general argument that I've made so far could be applied to other parts of political science. I chose international relations, I think, because of personal background and personal involvement.