There is a lot of bias on this forum, same as there is in life, anywhere, so yes, there will be times when things are incredibly unfair.
Having said that, if someone is telling people to kill themselves or he would do it for them, or whatever, could it not possibly be a symptom of an illness, and if the team were satisfied that he was better, or on meds, or more stable, or something then maybe he might be allowed back? Maybe a symptom of a problem might be given more leeway than a person with some form of attitude problem?
But yes, bias does occur here (maybe I see it more here than many places because I've ended up being on the wrong side of it), and yes, it is unfair, but unfortunately, that is a way of life. If you dont' agree with this person being about, keep your distance, presumably others would do the same if they felt uncomfortable and maybe that person may not stay here for long if he realised that past actions had consequences, or equally, he might change due to that.
I totally, TOTALLY get what you are saying though.