Restaurants gather people together around delicious food and everyone is able to enjoy themselves at the table with a meal and friends. Friendly engagement.
Parks invite people to have recreation at various stages in life, whether with team sports, a playground, just running around the grass, or a picnic. Friendly engagement.
Public transit helps people congregate on vehicles for the sake of traveling to a common destination, and therefore disparate people are united by this common goal of arriving safe and sound.
I could go on about all the public spaces that promote some kind of friendly engagement and socializing, but social media such as Facebook is calibrated and designed to put us at one another's throats. It's not good if we see a post and let it go by, we must lash out and correct or attack. Dislikes are as valuable as Likes in the Facebook economy. Hordes of censors are required to tamp down the inevitable violations that occur when people go out of bounds. Social media thrives and grows from attacks, libel, gossip, and falsehoods.
Of course this is all only an extrapolation of print and broadcast media as it came before. Nothing has changed since Moses broke the tablets and Luther nailed up his theses. But social media is concentrated and unadulterated poison.