Restrictions on the movement of people through territories -- whether they are owned by states, tribes, or individuals -- have always existed and will always exist. Try crossing through a farmer's land -- expect to be asked by a shotgun-wielding farmer what the hell you're doing there. Try going through Sioux country without permission -- you might lose your scalp.
In traditional societies, it is the duty of the tribal warriors to enforce protection. In postmodern societies, immigration is increasingly used as a tool, often by the state itself, to suppress, divide, and weaken the working class by stirring up resentments (of immigrants and natives) and intensifying the competition for scarce resources (from material objects to sexual partners). The state creates these antagonisms and then benefits when the resulting instability leads to popular calls for more state control! Moreover, whenever the state decides a native population has become too expensive or too troublesome, it can create a vast alternative pool of surplus labor through immigration.
For an anarchist like myself, the ideal is to decentralize political power and increase the power of local institutions outside state control. This does not mean supporting illegal immigrants, who aren't outside state -- to the contrary. Illegals represent a minority that is trying to impose its will on the majority by fully integrating itself within the state. Illegals oppose state power just as much as they oppose capitalism, which is to say, not at all -- they are here to make money and eager to take advantage of all the benefits of the welfare system. They are also seeking race replacement.
In my view, deputizing the citizenry, and allowing communities to decide who has the right to reside in their territory based on custom, would be the ideal solution. Modern laws enacted by liberal politicians like the Fair Housing Act and Equal Opportunity Act were created to stop this kind of thing from happening. This said, decentralizing political power away from the Imperial courts of Washington, DC, and empowering local governments to determine who's allowed in their territories, is a step in the right direction. From there, moving power from local government to local neighborhood watches becomes possible.
The Federal government's outrage at Arizona taking charge in immigration is indicative of just how much of a challenge to federal authority this latest bill really was. Imperial courts simply don't want their subjects running things on their own.
In another sense, one's reaction to the Arizona bill boils down to with whom one's racial loyalty lies. One cannot be for "humanity" because in the current struggle, one side will win and the other will lose.
I am not loyal to European America in itself, as White Nationalists are, but I have a lot more sympathy for American whites than the foreign people who want to replace them.
But in the end, the anarchist solution is easy: deputize everybody and see what happens. Only when cops become irrelevant to communities' public safety will anarchism become possible.