Answer:
The fungus may be endangering non-native palm trees, but that doesnt mean it wont spread to native ones. Even though the palms arent native to that area, they could spread to the native palm trees and start killing those as well. Also, the fungus could completely kill off the non-native population, or it could spread to where those palm trees are native. If it spreads to the palm tree's actual home, it could spell the end for that species of palm tree.
I hope this helps!