I've never visited a pro-suicide forum before, but your description about the site you visited sounds pretty accurate to what I imagine the social culture surrounding such sites would be. The whole 'cult out of misery' line you used sounds right - where people aren't actually serious about suicide, but it's more like they make a clique out of identifying (or pretending to identify) with that desire.
So now that the rant is out of me the real question is how do you view suicide and how do you view suicidal thoughts that stem not from outside trauma but from a simple lack of will to live
To me, having a 'lack of will to live' is not a natural state, because it goes against our natural instincts which are based on survival. We, just like all animals, have an incredibly strong sense of survival so having a lack of will to live suggests a disconnect from our natural propensity to live. Without trauma, I don't actually think it's possible for a person to have be in a state where they have a 'lack of will to live', unless it's a result of some chemical imbalance.
I suppose, based on your question, I think it's impossible for a person to have have a lack of will to live without there being external trauma. So someone who has never suffered outside trauma, cannot be in such a state without there being something chemically wrong with them. So perhaps you should define what you mean by 'outside trauma' - do you view having an abusive family/parents as outside trauma? I can't think of anything that doesn't fit into that definition - bullying, sexual assault, verbal abuse, child neglect, wars, these are all outside traumas that can cause a person to not want to live anymore. What is an example of a non-external trauma according to you?