They didn't have mics so I guess you could say that's your way of saying something. You did nothing wrong, because they didn't know how to play the game, didn't follow you (so they didn't know of the former problem), and they didn't seem to care about the game that much. I think that the game offers way too much for grievers, and nothing will stop the flow of stupid.
Tangenting on an experience of mine, I played a quick campaign game with a buddy. We entered the party and there were two guys in the game. We were in a LIVE party with a couple of our other friends, so we didn't talk to them. In the game, we did it all pretty well; the guys were slow, but got the message that zombies killed isn't an important thing and they followed us to the saferoom we were already in. The next leg, (No mercy 2) however, we got to the crescendo event, killed all the zombies in the room, then opened the door.
Our teammates started shooting us and we could see they were trying to communicate, so we invited them to the party when which they immediately started screaming unmentionable words to us in sentence we THINK were involving the door. They said they were "gonna kill all them ******* zombies before we went on so there wouldn't be any **** zombies to ****** kill!!" They were southerners (not a problem) but were about 8 years old. We jokingly told them that the "zombies" were infected, which caused the flames to rise higher. They shot us in the game, but we killed them in self-defense and went on through the level. The problem with this is the fact that they haven't played the game very much because CE's attract infected that aren't already there. It was funny and my friends heard it too so we all laugh at them to this day.