The difference between The Before Times and now is that it was historically hard to curate and communicate with a group of people who exclusively agreed with you. This had two primary consequences:
(1) You were constantly exposed to nice people who nonetheless disagreed with you about something / everything.
(2) It made you realize that you're the asshole, if you couldn't at least be polite to someone with different views than you.
Now, living in a bubble is trivial. It's also the subtle default on a lot of social platforms.