Trump's appeal comes from the fact that he has scapegoated an entire sector of the population. He says, "It's not your fault. Everything wrong with America comes from illegals. I'll get rid of them (ie: all the problems facing America). Trust me. I'm awesome... and rich!"
It's a very effective tactic. Leaders worldwide use it. Every time something goes wrong in North Korea, Kim Jong-Eun ratchets up the "It's the South Korean puppet regime's fault! Then engineers a situation were he can 'confront' them."
He also stirs up the ethnic superiority bit, extolling the Korean race and how pure it is. That the Chinese and Japanese have polluted blood.
I find it interesting, frustrating, and confusing how people hear what they want to and focus on small parts of a bigger picture.
Illegal immigration is an issue, and thank goodness for Trump bringing it to the fore. If he didn't, the political class would ignore it. Maybe, just maybe, Trump's antics will lead to a real solution, even if it's not Trump who implements it.
In the past, on this very forum, simply stating that illegal immigration is a problem, and calling for closing the border so that immigration can be legal, and somewhat orderly is enough to get a person called a bigot, a racist, or some variant of that.
There is more to what Trump is saying, but if you don't know that, me posting it won't sway you.
Disclaimer: I still don't trust Trump. He's too much of a snake oil salesman for me, but he is doing some good.