The way we learn to have crucial conversations with people who have beliefs or behavior we don’t respect is by doing the opposite—look for commonality.
But if your goal is dialogue and meaningful influence, you’ll only achieve those when the relationship and the conversation is built on commonality.
I have yet to see someone in a fiery discussion suddenly change his perspective because of how disrespectful and clever the other party was; not only do people not change, they stop listening.