You can't just look at this from HUM's point-of-view. If you were running UNH and your revenue was valued at 4 times one of your competitors (a short time ago at 6 times -- shows you how the market is starting to recognize that HUM is becoming more like its competitors) what would you do? It is one thing when that competitor is down-and-out and may not survive, quite another when they have turned it around and may even start to flourish.
From UNH's viewpoint, it's just a cheap way to buy revenue -- from HUM's viewpoint, they are too small to compete especially in a less benign environment than the current one. It doesn't mean HUM is being positioned other than to succeed -- it just makes sense for both parties.