You don't have to disagree, but you do have to share uncertainty the point of a conversation should be to increase knowledge. It can be shared or it can be a mutual exploration.
Mutual affirmation is the only uninteresting type of conversation, but some people do need it for emotional stability. It just tends to get out of hand.
I don't think Nostr lacks for diverse viewpoints, I think it simply fails to reward voicing those viewpoints. People simply don't engage with ideas that they don't like. Or they will to a point but back out to a shallower depth once their worldview is questioned.