"After all, what if Congress suddenly granted citizenship to all aliens now in the U.S. and declared that all who came here were entitled to stay, except perhaps known criminals and terrorists? Would that silence the "I'm only against ILLEGAL immigration crowd?" There would be no illegal immigrants, and the law would have been followed, so what objections could they raise, and why don't they raise them now?"
But the law would not have been followed. It would be a reward for law breakers.
The same arguments were used in 1986, at the time of the last amnesty. They legalized millions of illegal aliens already in the country, and promised it was the last time. Yet, here we are in 2006, and the problem is ten times worse then it was before.
What is to prevent this from happening in another 20 years?
As to your other points, I don't understand how you can say with certainty that there is really no difference between legal and illegal immigration. Have you run that theory by any people have have actually immigrated here legally? They may have something to say about that. Legal immigrants go through a long, arduous process, and, by and large, do their best to assimilate into American society.
As to the race issue, while that is certainly true in some cases, it does not define the sentiment of those who are opposed to illegal immigration. The media portrays it that way, but it is nonsense. There are many valid, and legal arguments against illegal immigration which have nothing to do with race.