His appeal is the same appeal that takes each of us in at some point; he offers easy answers to complicated problems. It’s tempting to believe that only the profoundly stupid will fall for this, but when a problem is outside your knowledge or experience and someone confidently announces they have a solution its pretty easy to let yourself stop thinking any further.

Also, there are a ton of racists and xenophobes out there who already believe they have the easy answers and like the confirmation of having them parroted back at them.