True. So why do it?
Why attack Ted Cruz if he's only polling in the middle of the pack? Or is he? Show me the plethora of attack articles about Mike Huckabee, Rand Paul, Marco Rubio or Rick Santorum. Hint: You can't.
Cruz is the target that gets their juices flowing. He also gets their donation money flowing.
If he weren't around, somebody else would be their target. But it would be less satisfying for them.
Imagine if Sarah Palin had run...