Even if it was indeed fully optional and nobody felt the obligation to share even though they didn't want to (which I find hard to believe), you have to consider that you're also imposing on the people who are listening. They didn't sign up for group therapy either and sitting through accounts of potentially tragic events might be an unnecessary emotional stressor for them (e.g. maybe they were also recently divorced or lost someone to an illness), especially if they're expected to go back to work and be productive afterwards.