I go back to my theory that he went there to troll the Puerto Ricans to help win support back home with the "base".
Coming up next, he will campaign in DC (where he doesn't appear on the ballot) and tell them they need to stop talking in Ebonics if they want to be a state.
I think a combination of that, and if you're going to lose big, and not get any delegates anyway, you might as well make it look like you lost on principle.
"My opponent, as you know, will say anything to win. I tell it like it is, if that lost me Puerto Rico, then so be it."