My personal experience essentially echoes what you've said. I've usually found that when I actually ask Trump supporters, which is probably most of the people I know, what they think and why, they are pretty candid about it. They will also voice frustrations, many of which I can understand or even agree with them on. There is a lot more common ground there than you might think.
The problem is that most of the issues are complex and nuanced. Not that surprising. Issues that impact the population of an entire country, or even a sizeable chunk of it, are bound to be pretty complex.
Here's where things go off the rails.
Kind of like you said, Joe Blow from Louisiana is often uneducated at best or a complete moron at worst. Joe Blow does not understand all the complexity surrounding the issues he's upset about and figures that if he doesn't understand it, neither does anyone else. He's also a little too proud to admit he doesn't understand it.
This is why Republican party completely abandoned an issues bases platform, aside from completely fabricated pearl clutching social issues like those scary tRaNs PeOpLe or AboRtIoN. They know full well that they have nothing when it comes to meaningful solutions to actual problems and if they did, the few supporters they have with functioning brain cells would start to ask to many pesky questions. A divide and conquer strategy is much simpler and more effective; albeit incredibly destructive.