I have many other people in my life besides myself, including my family, friends, coworkers, neighbors, and acquaintances. Taken all together that's my community. My relationship with each one is unique, but each relationship requires some conscious effort on both our parts to keep it going. I'm not devoting that effort to random strangers since they are unlikely to reciprocate, and I only have so much to give. When you say we are all in this world together, my reply is "So what?" I'm worried about the people I know IRL, and quite honestly there are jagoffs out there that I don't want anything to do with.
When people think of the wonderful communities of the past, it's all make believe. They were just as much about who was kept out, as who was a member. My grandparents lived in a rural community where most folks were Italian immigrants to the USA like themselves, and everyone knew or was related to each other. The unifying force for everyone in that town was the Roman Catholic Church, unless you got on their bad side, and were shunned. The Mafia was in the mix too, and you did not want to get on their bad side.