The fact it's so difficult to differentiate between the mission statement of an informal group and their actual behavior only adds to the problem. Maybe a group

The fact it's so difficult to differentiate between the mission statement of an informal group and their actual behavior only adds to the problem. Maybe a group behaves well in your locality but badly in someone else's. How are we to tally up thousands of incidents and say "Oh ok this group has a 90% positivity rate so you should feel friendly towards them."? It's impossible.