I actually think that the primary reason people disagree...and then keep persisting in disagreeing...is that they are instinctively defending and boosting their own ego at the expense of some other ego. The ego is defensive in nature. It fears anything different from itself. It attempts to achieve dominance and to get attention. It attempts to win and make someone else lose. It attempts to be right and make someone else wrong.

The ego is that in you which says,

"I'm all alone here. I'm irrevocably separate from all that I see around me. Everything and everyone I see is one of three things:

1. a threat (I must defend myself against it)
2. an opportunity (to satisfy some desire of mine)
3. something that simply doesn't matter to me (so I'm not interested)"

The ego is the nasty little thing in your mind that sets you at odds with other people, your own life, and the world. It is the essential cause of all your distress, and of all your wars. It does not love, it desires, bargains, lies, cheats, evades, covers up, battles, and competes.

To overcome the ego is to find your true Self, and once you do that everything changes. Love conquers fear. The sense of separation is replaced by the sense of unity and shared values with others.

I'm not saying I've done that in its entirety. But I am certainly working on doing it, and one of the ways to do it is not to do the kneejerk typical ego reaction into "attack" mode which the ego is so fond of doing in order to momentarily strengthen itself.