From my purely anecdotal experience with mentoring younger people, I've seen two main categories of venting: 1) Venting about frustrations by talking them through with someone who will listen. This forces people to put their frustrations into words and elucidate the narrative as they put it into words. This can not only help people identify their feelings and work through them, but it also forces people to decide wha…
In my experience, people who engage in #2 aren't - as you seem to be implying - people who are immature and lazy.
A lot of the time they're people who struggle with the executive function necessary to actually change their life, who feel helpless and just want validation after having been made to feel insane by the #1 crowd - crowd who gives them obvious (non)solutions like "eat healthier", and "just exercise more!", and shits on them if they claim it doesn't work for them or can't do it.
People love to rationalize why and how those people are motivated to not solve their issues instead of acknowledging that, just maybe, they really can't do better, really need help, and just gravitate towards the only crowd that won't treat them like moral failures for it.
I have been disabled by overwhelmingly debilitating fatigue for a third of my life, and human tendency to treat every attempt to describe my struggles as excuses to debunk so I finally "stop feeling sorry for myself" has been dehumanizing. The victimization isn't made up. People who REALLY struggle are systematically gaslit and abused by the overwhelming majority of people. The moment people catch wind of your inability to take care of yourself, they treat you as less than human and make up one reason after another to blame you for your struggle and exclude you from deserving empathy.
Rant over.