Disputants are talking less constructively to each other. Communication narrows and becomes limited to those who hold the same opinions. Each faction increasingly views the other through a distorted filter of suspicion, false assumptions, exaggeration, and misinformation. And while there may be no malicious intent to hurt one's opponent, it often results. Because the overriding goal is for one's viewpoint to prevail, there appears to be less concern about how that affects others, further exacerbating the conflict.
Action then begets counteraction.
At such a stage as this, original issues are superseded. The problem is now identified as a person. Public admission of having exercised poor judgment or unwittingly having made a mistake becomes increasingly unlikely. In this negatively charged environment, such an acknowledgment would open oneself to further attack, instead of empathy, grace, or compassion from the other side. As long as someone is viewed as a respectable and honorable member of the community, all is well.