Love love love to see Popper's work being more widely recognized. People typically know him as the "falsification guy", but his body of work covers so much more and is eternally relevant.
I'd be curious as to whether he would agree with you. I think one could make the opposite case to yours: Social media increases tolerance by exposing people to diverse opinions. Sure, this exposure tends to take the form of disagreement, argumentation, and occasional name-calling, but it's better than people living their entire lives exposed to only one perspective. And indeed, despite the carnage we see on twitter, attitudes are slowly becoming more tolerant over time (see, e.g., Our World in Data regarding women's rights, or trend surveys). These trends are not accidents, but are the result of conversation and criticism of the status quo. Social media, while messy, is an amazing tool for such criticism.
(I should say that I used to hold a perspective much like your own, but had my mind changed in this podcast episode).