I think you are missing the sublety here. He is telling them WHAT they want to hear as if to say this is WHAT I want you to be angry about. As very distinctly opposed to telling someone what THEY want to hear, ie they already have an agenda and Trump is talking their talk. An example is the migrants are eating peoples pets in Atlanta.....the whole MAGA ship now believes that migrants are to blame for everything. Who created that?His rhetoric is gaining traction because this is what people want to hear. Trump has the backing of some much darker far right forces behind him - including amongst high ranking members of the Republican Party.
This creating then owning of the narrative, is Facism and Trump has this in spades, its a fascinating topic. Its also has hallmarks of a Dictator who goes along the lines of "over there is a bad man, I tell you she's a bad person and so she is a bad person", and his followers moronically parrot back "there is the bad person, we hate the bad person" and the vitriol continues.
Do not think for a moment that most MAGA supporters had a view to start with. They are being used, like cannon fodder.