Short framing on one reason it's often hard to resolve disagreements:
[with some frequency] disagreements don't come from the same place that they are found. You're brain is always running inference on "what other people think". From a statement like, "I really don't think it's a good idea to homeschool", you're mind might already be guessing at a disagreement you have 3 concepts away, yet only ping you with a "disagreement" alarm.
Combine that with a decent ability to confabulate. You ask yourself "Why do I disagree about homeschooling?" and you are given a plethora of possible reasons to disagree and start talking about those.
In light of reading through Raemon's shortform feed, I'm making my own. Here will be smaller ideas that are on my mind.