On leadership- lessons learnt while backpacking

Last weekend we had a mutiny on the backpack to Thunder Swamp in Eastern PA. Initially, 7 of the 12 members decided to bail out at the end of the first day- we were a little bit lost, it was hot and humid, the bugs we eating us alive, we had no planned camping site and there was a chance of rain.
I am puzzled by the whole incident- we backpack because we want to. We sign up weeks in advance without full disclosure of what the conditions are going to be and we do it because, at least in my mind, because it is an adventure.
So, what happened?
Leadership failed.
These trips have a leader - he is supposed to keep the group together. First, the group was too large and had different skills. The group ended up being split in 2, the fast group and the slow group. Clarity on the rules of the hike were not reinforced at the start of the hike - so the split was difficult to handle because basic rules, like waiting on trail intersections, were not kept. This was partially the cause of us getting lost.
Second, the leader has to have the respect of the led. During the hike, there was a lack of 'respect' to the leader- in a jocking way- but reflecting the fact that some of the team did not hold the leader in high esteem. Words and actions do matter.
Third- the uncertainty does not help - not knowing where we were camping created a sense of loss on some of the members.
The dissenting group had a leader that generated an attractive alternative- a cold bear and comfortable bed for the night. For some this was an option- but then, why do you backpack?
Lessons learned- keep the group small, make sure that expectations and rules are clear and do not take abuse from the team.