This is helpful in any controversial conversation. Here is a way that works. Get them to agree to argue for 1 minute and then it’s your turn for 1 minute and so forth. There will be absolutely no interruptions. If they won’t agree, then the conversation is over and also your support of them is over unless they agree to the 1-minute method of argument. Once there is agreement, we can conversate normally.
Flip a coin to determine the first speaker and they get 1 minute, and they can pause or talk with no one else speaking. The pauses help immensely. Then the next person can pause or talk for 1 minute. Sometimes when you begin to pause after saying something, you think of something else you want to add to your 1-minute turn.
This method provides for a much more thoughtful way. Strong disagreements result in anger, and this is the only way to get thought it without making things worse.