There is a writer's group between friends that I go to. Its not really public, and was set up just for fun. We enjoy writing and share our stories with each other, then laugh and giggle and eat snacks that we all bring. Afterwards we'll play Apples to Apples or Phase 10 or whatever easy and fun game is brought. I wouldn't say its dominated, but there is a "leader", who organizes the time etc. Perhaps it could be a difference between public groups, and just a bunch of friends getting together.
Everybody usually has helpful insights (or they just don't care and like to hear the stories) most of them write fanfictions, so there is a lot of nerd-related topics and fandom going on. Personally I've not contributed too much, but I have plans to create a novel off a short story I created. They liked the little pieces I've crafted so far, but again, they don't seem so critical as just enjoying a good story. We'll offer ideas/insights as needed, and I'm sure if I really asked for help they could give me some good pointers.
If you can't fit into a public group, perhaps try local with friends/people you know who like to write?