The basic problem is that it is mainly California that carried the popular vote to Clinton, and California is clearly a state that has issues with exposing illegal immigrants. Aside from the fact that its cities which have its major populations are “sanctuary cities”, the state itself as a state is musing whether to become the first sanctuary state. It is self-evident why one does not trust California. And if one believes the mentioned poll that over 10% of the immigrant (non-citizen) population actually voted (and one logically assumes the vast majority of those would not vote for Trump!) the numbers speak for themselves.