That group is unsafe and they sound like a bunch of d-bags to be honest. I would not ride with them again. It's usually a few people who set the tone for the group either intentionally or unintentionally. Personally I would start my own group with a few of the guys with clear rules about stopping, re-starting and ride etiquette. Nothing chaps my azz more than riding in a group and knuckleheads up front do out of the saddle sprint starts stringing everyone out making the ride turn into closing gaps the whole time (unless that is the purpose or a training ride designed to be that way). If it's supposed to be a group ride then group dynamics need to be adhered to. If it's a "drop ride" then all bets are off...ride as an individual not a group.