The issue here isn't whether it's true, but why it has not tarnished his image. A lot of images have been tarnished by rumors or allegations, whether based or baseless, so why is the case of Murray different?
Maybe the alleged incident was not credible/juicy enough? It's not like a security camera caught Murray smacking around his wife in a hotel lobby or a picture of his wife with a black eye leaked. Anecdotally, I live in Charleston where Murray/his ex wife live. Some years back a coworker was dating a girl who was a 911 dispatcher, and apparently his wife was well known to the dispatchers for making spurious calls on Bill. So my guess would be all the celebrity gossip rags probably didn't have anything good enough to run with.
