> After working some years at an organization

How many years has this person worked at reddit?

> Is it not fair/humane to give employee a chance to hear charges and to tell his/her side of story so that independent body can decide fairly?

The employee does have a chance at redress by an independent body. At least in California, they can sew their past employer for wrongful termination. It will probably cost them a lot of money, especially if they were rightfully fired, but who were you hoping to pay for the 'independent body' to defend? The employer can't, it would be a conflict of interest.