I think you're absolutely right in that things used to be more volatile. The mid-19th to early 20th century US are great exemplars of this. But even though in the modern era (I'd say mid-'30s on to the early 10's) after the advent and refinement of mass media felt like an era of more reasoned dialogues on the balance, I really think it was a mirage that's only reinforced by our ability to look back at niche circles where it was actually the case in hindsight.

Mass media and educational institutions bounded our collective capacity for political thought through their selective exposition of certain ideas, meaning people in the era were less likely to have mutually unintelligible or incompatible beliefs about the ordering of society, and that they were similarly incapable of conceiving of such a political enemy (communists notwithstanding)

As a result, we never collectively developed the rhetorical tools or emotional capacity to consume or have reasoned discussions that tackled the fundamental aspects of our culture or its organization that conflicted with our preconceived notions, because we never truly had to.

Social media has given air to ideas that would have historically been suffocated in the cradle or domesticated long before we were ever exposed to them, and as a result I don't think it'd so much degraded our capacity for political dialogue inasmuch as it has how sheltered we've collectively been, and how much less refined and rational we actually were.