I only draw the line when they begin thinking less of people (ie evil or stupid or both) because of their politics. Most people think their politics are in the interests of everyone and very rarely do they construct them to purely harm other people and benefit themselves. Often, subconsciously, they advocate for things that are self-interested and harmful to others, but that's rarely their admitted and conscious intent.

There's a fair bit of psychological literature suggesting political "temperament" is innate and I tend to think that's the case. I even think we evolved innate differing beliefs because such construction benefits to us - ideas have to compete to win. Overall, I tend to see disagreeing as natural and beneficial.

I personally align with individualistic politics, and think they're "da best," but I accept how unpalatable they are for a lot of people who have different priorities.