I strongly despise empty "we need to find a consensus" rhetoric, but I'm wondering: there must be tried and true mechanisms and techniques to encourage people to give up entrenched positions.
We recently had pol.is on the front page which made me think of it again. But I'm mostly not searching for a tool.
What are key words I could search for? The moderation and coaching literature is really vast, and I don't have a good sense of what is practical and valuable, and what is just a fad.
(I don't have a team lead role or any disciplinary power, so bonus points if those techniques can be used bottom-up)
The simplest thing that might work is removing that attitude from the workplace culture.
It's not a preference worthy of accommodation.
Good luck.