We have agreement on most goals and their national importance. "Support for US demand for labor" is vague. Maybe something tied to unemployment rates? As US workers move up in education and skill levels, lower skill jobs become undesirable so I think a lot of those low level jobs would go unfilled without immigrant workers. The unemployment level remains at a level considered full employment but it never remains the same.
Do you have any goals to add to the list? I must have missed some important ones.
What other jobs are going unfilled that we need so many low-wage immigrants for? Hotels and restaurants? If so maybe we have too many hotels and restaurants. Low paying jobs means the taxpayers have to pick up the tab for increased social costs and I don't see how they're worth it. I've yet had any of the open border enthusiasts persuade me they are.
In the fast food industry traditionally teenagers did that kind of work and in areas with large numbers of illegals they're stealing the jobs from them. Maybe they're not needed there either. We won't know until we start enforcing the law.
If it were up to me we'd keep immigration legal at moderate levels and for those with skills, no guest worker programs except for possibly agriculture. Even if we stopped immigration cold today several studies have concluded the birth rate will continue to climb for the next fifty years so I see no real reason to continue this flood.