Because if the government is unable -- unwilling, actually -- to enforce the current laws now, it will be no different under the post-amnesty regime. Even if the bill passes, nothing will change in any fundamental way.
Why? Because when all these new Z-visa holders become "regularized," they are "out of the shadows." Employers will no longer be able to pay them sub-standard wages off the books. The minimum wage laws will apply to Z-visa workers.
The result? There are another 20 million illegals willing to come to this country to work for the same sub-standard wages the current crop of illegals are working for now. And the same employers who hire illegals now, will hire the new wave of illegals, for the same reason they do now -- they are the cheapest source of labor.
Amnesty will price the "regularized" illegals out of the market.