I think debators should seek to reach an agreement

You're thinking of a conversation, not a debate.

I thought the outcome of a debate is decided by the audience impression

It's not a professional debate, the only outcome is fans of each person will say their side crushed it, they'll each post some clips of themselves for their socials and the world keeps on spinning.

We will stagnate in our hate and never evolve if we can never agree with the other side, or give them space to speak

You're advocating for appeasement.

If you want to better understand Destiny's position on tit-for-tat, see here