Why Is Thanos Stronger Than The Hulk?

In the run-up to Infinity War , Avengers and audiences alike are majorly concerned with the potential destruction that could be wrought if Thanos were to get his hands on the Infinity Stones - but how strong is Thanos without the Infinity Gauntlet in the first place? Thor was then capable of feats such as reconstructing the Earth's Moon,29 willing the Asgardian monster Mangog into nothingness 30, successfully challenging and defeating an alliance of Surtur and Ymir 31 and by focusing his entire power into a hammer throw even decapitated a Desak-occupied Destroyer.32 Thor later briefly acquired mastery of the Runes, and a level of enlightenment that allowed him to free Asgard from the eternal cycle of Ragnarok, becoming even more powerful than his father.
Not even ashes would remain of Superman if Thor would strike at him directly with such a bolt of pure energy, and, to be perfectly honest, Thor doesn't really need that much firepower to blast, for instance, anything including a Ship to Atoms-See-Avengers-82 (vol.1). And, finally, Thor can effectively direct multiple lightning strikes as he once did against several Celestials at the same time-Thor-300.



That's because he is so much more powerful than Hulk that all he really needs to get him out of the way is a simple slap; Thanos is very low Skyfather tier (which puts him a level above Thor, Sentry, Hulk, Hyperion, etc) while modern Hulk is multi solar system level and could be argued to be galaxy level.
With a career dating back to the early 1970s, he is best known for "cosmic" tales and space opera; for revamping the Marvel Comics characters Captain Thanos vs Hulk Marvel and Adam Warlock; and for creating or co-creating the Marvel characters Thanos, Drax the Destroyer, Gamora and Shang-Chi, Master of Kung Fu.
With a career dating back to the early 1970s, he is best known for "cosmic" tales and space opera; for revamping the Marvel Comics characters Captain Marvel and Adam Warlock; and for creating or co-creating the Marvel characters Thanos and Shang-Chi, Master of Kung Fu. Death and suicide are recurring themes in Starlin's work: Pers James P. "Jim" Starlin is an American comic book writer and artist.

Well first of all Hulk's activity or lack of same in the rest of the movie indicates that he was something less than fully motivated and so does his role in Ragnarok where he starts indicating that he's resentful at being used by his Banner half and the Avengers.
Remember Hulks power comes from Anger, now if Hulk is being beaten by Thanos fear and doubt starts to creep in. This then leads to these emotions overcoming his anger meaning he would actually weaken meaning Thanos can cause more damage leading to him weakening more.
Basically, we've already seen him hold his own against a Thor who was amped beyond WM, and in his first appearance we've seen him cause the same level of destruction as Worldbreaker, and Thanos is much more powerful now (well, he's supposed to be, we'll see what the writers do with him).