It's part of maintaining the fiction that everything is perfect in 'God's orgainzation', and that those who are regular in attendance and service would never do anything wrong. Even when the Victim is NOT considered spiritually weak, the fact that they brought up the issue makes them uncomfortable (doesn't jibe with beliefs, things like that don't happen in God's organization), so it's easier to blame the victim than confront the facts. Anyway that's my take on it.
I agree,well put
also I think the JWs need to have unity at any costs, so it's like a wolf pack mentality shun the weak(victim) stick with the stronger pack.