Why is there such a strong duality in politics?

Question

I’m talking about the struggle between the right and the left, which in most democracies are pretty much equal and often change. For example, in America, conservative Republicans vs. Liberal Democrats have been fighting each other for more than two centuries, or just 16 years in Hungary. I don’t understand how one can identify with an entire ideology so much. For example, I give truth to one issue and another to another. I basically consider myself a Social Democrat, but I would never vote for the MSZP. I find gay marriage and adoption acceptable, but multiculturalism is bad. This is just one example now, but as if I were alone with this opinion, as if you were a member of a group, you had to agree with everything. 

Answer 1

In my opinion, this may have happened to us because people are forced to politicize on the basis of emotions, there is so little reasonably right choice from today’s political elite. This is compounded by the fact that many silly people in the media and even on the net believed it to be authentic, but meanwhile form their opinions based on false, propaganda information instead of looking a little behind things. So, of course, it’s easy to divide a country, and that usually favors current power.