"...without any consideration..." is important to point out. This has been a pet peeve of mine since I was very young. I guess I was always taught to question everything before internalizing as truth. Dad often played devil's advocate with me to encourage me to think and defend my opinions. What would you say to the notion that perhaps swarm mentality is born of each person's desire to be part of something bigger and simply the desire to have a cause worth the effort. I could put this much more eloquently but have not had enough coffee yet this morning.
In the past (regardless of how you may feel about it) the church was an integral part of any community and family. To some degree each individual felt a part of the church community. Although there were still vigilante groups and lynch mobs I would submit that there were less pointless band wagons and apple boxes. This could be also because living was more difficult then and one was pre-occupied with day-to-day sustenance, where as now we have more frivolous time.