[boycott]

These folks were failures at making their own nations more prosperous. They come here to be failures and make all of us less prosperous.

Why do they not fight to make their own nations better? It’s too easy for them to ruin our nation.

[El Cid]

I blame them less than our Government (and the Media and wolves in sheep clothing that encourage this behaviour).
Although you are correct that these illegal invaders should work to improve their own nations, it is human nature to want something for nothing. It is the Government's responsibility to uphold the law and protect our borders and Constitution. Their dereliction to duty, and those that encourage them to act in this manner, are the ones at fault.