But inevitably you are not explaining anything, but rather stating that europeans are inexperienced and bluntly said stupid on the topic of US politics purely because of the fact that we were not born on US soil. Nationality makes zero difference on someones capability to learn and research something.
Back to the topic. The political landscape of our virtual world is a coin with both of its sides being replicas of the other. Both parties portrayed similiar agendas which caused a group of people to create a separate party that would focus pushing the agenda that was missing from the existing two. In real world the same would happen if for example we would see one state's both rep. and dem. parties with left sided agendas. Existing voters who have right sided political views wouldn't vote for the left supporting parties, they would find an alternative from the minor ones or create their own to ensure their side of gets represented, and even push it further if majority was met. This is an entirely existing process in California for example. Anyone who legitimizes their party can officially enter elections with their own party on a state level.
We cannot duplicate our political landscape from California for example, because it is already flawed looking at how different the political views of each party and their real life counterparts are.