I don’t know about hate but I think they dislike him because he is an overly ambitious young establishment hack who would not wait his turn and jumped the line, which is frowned upon in Calgary Ted’s Bushy establishment circles. Pulling self promoting stunts like calling McConnell a liar just to build his “outsider” cred probably didn’t help any either. On top of that he is a very unlikeable guy who hangs around with other thoroughly unlikeable GOP establishment types.
I think Cruz really does hate him.