He says "BIG OUTRAGEOUS THING, with long list of qualifiers that follow" the media reports the first part and completely misses the second. Mostly it's a great way to game the system to get free media attention.
It's a manifestation of dog whistle politics. He says this stuff and we understand the implication that Mexicans are coming here and screwing things up. But his supporters can deflect criticism because the literal words are sufficiently vague that you can accuse people of inferring too much.
I believe that he gets to have it both ways: those of his supporters who are themselves isolationist or maybe even racist are excited to hear him say they same things they say. Those who are more moderate take this "he's just misunderstood and misquoted" tactic.
He says "BIG OUTRAGEOUS THING, with long list of qualifiers that follow" the media reports the first part and completely misses the second. Mostly it's a great way to game the system to get free media attention.