If talking to random strangers worked then people would be doing this more often.

The problem is that it's usually extremely unlikely that you actually have something in common with a random stranger. I mean it's fine if you enjoy popular things and do typical activities AND you like having lots of casual friendships, but if you have a distinct personality or you prefer to build deeper connections, then "send to all" approach doesn't work.

I started being nicer to people and I realized I found myself taking part in conversations that I simply did not enjoy.