Consensus isn't a reasonable goal or even desirable when you're discussing things which are more complex than, say, cut and dried technical facts. I can achieve consensus among mathematicians by providing a proof. I can achieve consensus among scientists by performing repeated experiments. I can achieve consensus among philosophers by, well, killing all the other philosophers. But if I don't do that, I can learn a lot and better develop my own positions and thoughts by having discussions with them even if I'll never force them to agree with me.

You don't have to particularly care for 'soft' discussion and reasoning, but that's not a problem with it, it's a personal preference of yours which is extremely uncommon among the general population, however over represented it is on HN. Every discussion about anything nontechnical has this 'soft' property.