Now, admittedly, its an unfortunate thing that legals seem to be leaving as well. However there's a few things everyone should stop a moment, think about, and then re-evaluate the situation as I'm seeing a lot of people immediately emotionally jumping to the "Grrr its saying legal people are leaving! That shows its racists or you're racist for liking it" type of view...
1. The story gives little to no indication of how much the variation is. Is it primarily legals leaving? Primarily illegals? Pretty even split? Is it a handful of legals or illegals and the rest the opposite?
2. Adding too that, it gives us little to no details about the legals or illegals that are leaving. Are they young or old? Are they extended family to someone that is of the opposite legal status of them?
3. It gives little to no information about what is actually spurring the movement. Is it fair of discrimination, is it principled disagreement with the law, is it because their family is leaving, etc?
All of these factors matter and are important before really being able to condemn the possible leaving of legal Hispanics as being too excessive of a cost of this program. For example, if the majority of the "Legals" that are leaving are children who were born in the U.S. to two illegal parents and they're having to leave the state because their parents are then while I see that as unfortunate for the children I do not think that's a problem of the law nor something that is reason it shouldn't exist. While under 18 Children are tied in a significant way to their parents and their parents choices and while generally its unfortunate to "punish" the child for the Parents poor decisions such happens day in, day out in this country, and I see no reason why a special exception could be made here.
Similarly if most of the "Legals" are leaving because their family or friends are illegal and they're leaving, then again, I don't think this is an issue of the law or something to truly be concerned about. This is not forcing them to leave, it is not out of "Fear" or "pressure" from the government, it is them making a CHOICE to move so they may stay close to criminals that they care about.
Additionally, if people are leaving the state simply because they disagree with the law I see it as no different or more condemning of the law as some kind of "evil" thing than people leaving the state because they disagree with a tax increase, or too many business regulations being passed, or because it does/doesn't allow gay marriage or late term abortions, etc. You don't get extra sympathy for leaving a state because you dislike a law simply because you happen to be hispanic; you're not special, you're not a snow flake, its not unheard of that people leave an area for displeasure with the government there.
Now, if the majority ARE leaving because they feel they're going to be discriminated against I think that's unfortunate and I think Arizona should make an effort to reach out to those communities and educate them about the truth's of the law, of which is being twisted continually and routinely all the way up to the administration of the President and is likely stirring much of the fear leading to the fright of being "Discriminated against".
However, again, them THINKING they're going to be discriminated against and that being their reason to move doesn't mean the law is evil, or bad, or should be too blame for it any more than black individuals leaving a city because they THINK they could be discriminated against by being frisked simply for being black (Being frisked relies on the exact same legal standard as the card check does).
Ultimately, without that information, its hard to make a judgement on how bad the side effects being caused by this bill are. However, from what's stated in the article, illegals are leaving so at least in some way the main focus of the bill is having a positive effect on that particular issue.