Need is a rather absolute term. No, we don’t NEED immigrants. Do they help our country, does it help some in the shitholes of the world, and is immigration something that should be encouraged? Well, those are different questions than if we NEED immigrants.
Some things you might consider though:
If there are 81 million people starving, and we can help one million of them, shouldn’t we? Is the fact we can’t help everyone really a moral justification to helping no one? Isn’t this logic as moronic as if someone said ‘One person starved to death in America last night. Clearly we need to shut down all assistance to the poor across the nation since it isn’t doing any good…’
The immigrants who come into this country often had no opportunities at home. I don’t care how energetic the person is, if the most advanced job in their home nation is making goat cheese then they’re going to become goat cheese makers. A person who comes to America, gets educated, earns wealth, and later in life goes home and funds a school will be doing far more good for their home nation than if they stared at a goat udder for decades.
There are parts of the world where people aren’t leaving to improve their lot in life, they’re leaving because if they don’t then they will be killed. From a humanitarian point of view, rather than stopping immigration, perhaps we should have an open door policy on those from Sudan or other African nations ravaged by war, minorities in China, and even Mexicans caught in middle of drug lords.
From the flip side, consider the benefits to the US. Chinese, Irish, Jews, Germans, Vietnamese, etc. They all have two things in common. One, at some point in the past they came in large numbers to America and some were ranting how they would be our downfall. Two, those subgroups have improved America far more than they have ever harmed it.
Besides, if the US shut off immigration, the richest nation in the world would basically be looking at those worse off than us and going ‘Gee, sucks to be you.’ Not exactly the type of foreign policy I’d endorse…