It's weird that Rubio is getting called out for doing what they all do.
Each of the candidates has memorized a few talking points and they never go off-script. None of them do. Even Christie focus-group-tested the way he would hack at Rubio, to do it in the optimal way.
The gauntlet that candidates have to run is inhuman. No one, no matter how smart or eloquent, can avoid a career-destroying gaffe at the hands of the political press. If you ever had a doubt about this, the Dean Scream should have settled it. Don't get caught being human.
Of course Rubio totally deserves this. He is a robot. More than most.
PS: I liked the way Trump broke the fourth wall and told us the audience was made up of Republican donors. I haven't heard any of the reporters say whether or not that's true. The way Trump said it, it sounded true. (According to Factcheck.org, it's not true. Not totally surprising.)