One thing that has been helpful for me in understanding immigration is to think of this as a case where the law (an aggregation of what the public over the past several decades thinks it wants) is in conflict with what the public actually wants, as expressed by its interpersonal and economic decisions.

Americans are overall extremely happy to transact with, socialize with, be neighbors with, have children with, and educate the children of undocumented immigrants. This strong expression of what we really want (in our actual decisions) creates a powerful incentive pulling people here. Put differently, if a majority of Americans hated undocumented immigrants, impeded them at every turn, and boycotted their labor and the services of businesses that hired them, the number of people who come here would be very different.

In an analogy to tech policy, when you ask the average voter "should people have access to private communication tools that are private even against legitimate warrants under the rule of law, even in cases of serious crimes or terrorism" everyone says "no!" But if you ask them, would you like an app where your own messages are private, many people choose that app, and many engineers and major publicly traded companies choose to build such apps.

We explicitly run a society that uses multiple dueling measures of what people want, the main ones being the will of voters and peoples' choices in the marketplace. Immigration is one place where those two measures collide, and here we are.

As a result, I think it's insufficient to simply point to the law. Maybe the laws are wrong. If we have a strong signal that this is true (in this case the economic and social reality of broad acceptance and integration of undocumented immigrants) we should be especially cautious to be reasonable in how we enforce the laws. This is an important principle in freedom-based societies.