We tend to think that people who defend ideologies diametrically opposed to ours are not only wrong, but evil nests in them, when good nests in us. This happens because political ideologies have a high tribal badge component..
When it comes to right / left dichotomies, the effect is even more profound. However, both positions pursue good, even if it is different.
In the book The Mind of the Righteous, Jonathan Haidt speaks of moral matrix to describe the moral paradigm upon which one considers right or wrong. That matrix is not born as much from reason as from intuition. It is partly biologically determined by our genes.
The moral matrix of the political left, in the United States and elsewhere, is based much more on the foundation of care, protection and general empathy than the matrices of conservatives.
That is to say, a person on the left can wear a sheet on which he says "Save Darfur" or a sticker with a slogan that invites people to protect innocent victims. A conservative, on the other hand, will also invite you to feel care, protection and empathy, but not so much to people from other countries or animals, but to people who have sacrificed for the group. That is to say, it is not universalist: it is more local, and it is imbricated with loyalty.
Conservative Christians send large amounts of money abroad and provide great help to the poor, but it is usually done through missionary groups that strive to add converts to the group. It remains a form of parish care, not universalistic care.
The instinct to empathize with the pain of others, that is, the moral matrix of caring for others, evolved in response to the adaptive challenge of caring for vulnerable children. It makes us sensitive to the signs of suffering and need; It makes us despise cruelty and want to take care of those who suffer.
Depending on our ideology, we will lean slightly more towards one more group empathy (take care of ours) and less general (care as a symbol, even if that means taking care less of ours). Both positions have their pros and cons. Both, in turn, are necessary to respond to the needs of complex societies. In that sense, diversity is our best weapon. And right-wing and left-wing voters, united, make this world a better place in different ways.