What "principle"? Anyway, here I go, "in case you don't remember your U.S. History". (Thought that was a condescending statement, but at least I made further than
@HighStickHarry 
, who's statement I agree with about "immigration haters", talk about broad.) So slaves, who were torn away from their homeland, put on a ship to possibly die, sold as a commodity into hard labor, raped, beaten, hung and bred like an animal, then ran away to the north to seek freedom are the same as someone who breaks our laws and illegally enters our country? Yes, you assist to round up people for breaking the law, you don't for people brought here against their will. And you sure as hell don't act like there's one similarity between the two.
Honestly? I can't believe I had to answer this for you.