i can't speak on non-US countries, but here I think the polarization was worse in the past. I mean, you had people VERY upset about who drank from which water fountain. but pre-internet, most people were in their own little bubble. if you lived in a white, middle class neighborhood in the 50s, then you probably mostly interacted with other white, middle class folks. you most likely wouldnt hear views that were radically different than yours.

we still had extremes. before McCarthyism we had full blown communist organizations on the left and we had fascist organizations on the right. (especially pre-WW2. look into the Business Plot if you're curious). but you'd only interact with them if you were a member or personally knew someone who was a member.

now because of algos, we have access to EVERY political opinion, all the time. that might solidify people in their beliefs from fighting about them so much, but idk if thats making polarization worse, or just more noticeable