Ripsnort humans are social creatures and make assumptions based on others about the company they keep. Also some of us don't forgive people when they cross a certain line of behavior that harms other people.
Your right its a freaking game. But in the case of Voss he purposedly fabricated the truth and bilked people out of money, etc., etc. (whole TAS situation).
So yes, its a game but at the same time its human behavior to show disapproval of one's actions that harm others by not associating with them. Which is why 13th TAS originally removed him from their squad and point out they have no involvement with him or the whole TAS scam.
Your right its a game .. but say you found out that one of your squad mates in real life was a person you highly disapproved of (Bill Clinton
) or say one of the executives from Enron, or a pedafile, or whatever. Yes, some people would say so what while others naturally would say I can't fly in a squad with that person or want people to think or make assumptions about me because he is my squaddie.
This is the probable reason why 13th TAS (Icer) posts these clarifications.
As for others .. they are pointing what Voss did in the past and believe they are warning others to watch out for what he is capable of. Basically they are in the category of "neither forgive or forget," rightly or wrongly .. depends on your point of view.