Part of the Dem strategy... let the GOP tear each other apart for so long until many independent voters will not even consider voting GOP. Seems like the GOP candidates would, for their own sakes, focus more on Hillary and Bernie.
What you said, so true: “Cruz, Trump, Rubio destroying each other making it easier for the Dems...”
There is nothing that the Republican candidates will say that will reach the depths of what the dem machine will say. Better to toughen up now, get it on the table and develop strategies to deal with it.