The heart is perhaps the only muscle in our body that is stronger when it is soft. Firmness, strength and the ability to harden are key to core vitality throughout most of the body including our sexual organs. Hardening our heart whether it is in response to a political reality or a difficult relationship turns us into our own personal brand of fundamentalist. It is a slippery slope from the tightening in the chest to a self righteous stance about how the world should be. It happens even before we see it happening.
If our language is an extension of our soul, then how we talk about things reflects our ability to feel and know them. Rigid positions accommodate a narrowing of our language and support a limited view of the other side. It can be painful to let in the depth and nuance that allows other people act irrationally, even seemingly against their own self interest. This is another disadvantage of relating to the world with a hardened heart, it is hard to tell when you are winning, because both sides lose something when the relationship is stuck in polar positions.