The rape case was known about while Billups became a 5 time all star and 3 time All NBA player. He was one of the most respected players in the league, and that hadn't changed after his retirement. What has changed?
Again, he wasn't convicted of anything. The Blazers did their own internal investigation - hiring an ex-FBI agent to conduct it apparently - and they're willing to take the plunge and accept all the heat that comes with it. And they may lose some business over it.
That's their right. If I had to guess they viewed it as a last ditch shot to keep Lillard happy.
Maybe someone should go talk to Antoine Walker or Mercer about what happened. Walker I believe has even worked for the league counseling players in recent years.