I'm not saying murdering everyone is the right alternative, but if you think trying to balance political power by "winning debates" or something seems reasonable, that ship has long sailed.
I know everyone hates it when people “both sides” things these days, but one thing I do see both sides having in common is a refusal to honestly engage with and comprehend the other position. This doesn’t mean agreeing. It means understanding what someone believes and how they might have gotten there.
Where the echo chambers and other things that you mention do come in is in reinforcing that dynamic, in reinforcing each side seeing only a straw man version of the other.
You're equivocating between reasons as in causes and reason as in rationality.