It's an awful mess. Trump explained it perfectly in some of his campaign speeches. Mexico's had it made for many years. So why would it want anything to change? It hasn't contributed enough on border security. And that's because its Governments are usually corrupt.
The US has no choice but to act. The border must be secured and Illegal Immigration must be ended. If Trump makes a serious attempt at accomplishing that, he'll always have my support. It's time for change.
Hating on Mexicans won't fix what's wrong in your life, buddy.