The scenario I had in mind was not debate, just information exchange. Imagine a person meeting friends in a bar, or at a dinner party. They're likely to exchange stories they read about in the news. "So this politician said $outrageous-thing!" (taken outside of context, but who cares), says the person. "Oh yeah, all X are bad, have you heard of $event-that-never-actually-happened?", replies the person B. The conversation goes on. Ultimately, little to no truth was exchanged, but people bonded together. Fiction served its social function.
IME, this is how most not-directly-impactful knowledge is used by people. I've been in countless such situations, and it's painful for people with stronger affinity to truth. Unfortunately, under the guise of "good manners", society teaches you to shut up.
We shouldn't avoid debate. We just need to ensure that people debating are there to discover the truth, and not just pick up morsels to share at dinner parties.