Are the Dinobots unintelligent or just very aggressive?

I'm talking about the movie version. In Transformers 4, Optimus frees all of the Dinobots from their cages and asks them to help fight against Galvatron. Instead of talking it out or anything, Grimlock up and attacked Optimus right away. Also, none of the Dinobots speak throughout the whole movie. Furthermore, after Prime's fight with Grimlock, he appeared to "tame" him like an animal, by riding on top of his dinosaur form. Does all that add up to them just being more of like animals/lesser or unintelligent transformers? Aren't they supposed to be "Legendary Knights"? Or are they just very aggressive in nature which gives the feeling that they're not intelligent?