It is easy to explain her actions (as well as those of other 'Conservative Luminaries' that have fallen off the wagon) - the explanation is that 'it's just business.' There are some personalities who are true conservatives, but then there are others who are simply in it for the revenues it brings. In the same way there are some people who are in a particular field of work for the passion, there are others who are in it for the simple fact it is a like of business. A source of income. Now, I cannot read Ms Coulter's mind, but think about it for a minute. You are a lady with a well honed ability to write. You are looking at a way to translate that into a living. You identify a particular niche that is high potential - conservatives. There are not many women writing/editorializing in our circles, thus she would instantly stand out. Her books get bought. Her views get listened to. Before you know it, she's both rich and famous.
Life is good.
The problem though is what happens if your target demographic makes a decision to support someone you don't like (the SC/Newt even that drove a wooden stake into the hearts of many RINOs)? Suddenly you lash out in a manner that makes the target demographic realize she was a RINO all along.
Which is why it is not at all shocking why people like Coulter and Beck (not to mention the likes of O'Reilly) act the way they do. It is a business to them. A very lucrative business. It is only that now it seems the target demographic is taking actions that are not 'prequalified' by the RINO elites.