"It would be really nice if you wouldn't consistently post such balanced comments"

Lol. Believe me, a few people on social media agreed and I can't see their stuff any more. ;)

"I'm trying to think of comparable societal changes that we've been able to reverse at least sufficiently ameliorate. "

Similarly having a hard time. This particular one got reversed temporarily each time new mediums were invented. Then, the people using such tactics mastered them for the new mediums. Helps when the start rolling in money then use it to ensure the dominance. The social media has more potential to counter this than ever if they just adjust the algorithm to bridge the groups a certain percentage of time. They can mostly create a comfortable experience for the ad revenue but should make sure articles citing at least half-ass sources float into opposing feeds while letting bullshit stuff Snopes counters fall lower. That simple change, applied to everyone, might have a significant effect on the situation at least for moderates or rational people likely to effect change.