Earlier quoted context omitted.
What’s the worst that can happen if we let them in? Our economy improves and our crime rate drops?
1. There's another billion waiting to enter. 2. There is legal process of entry, they should follow it. 3. Illegal immigration drives down wages, crowding out the most vulnerable citizens of the US. 4. A country decides how and when people are allowed in. There are numerous downsides to mass immigration including stress on services like health, social services and accommodation. Again, to the detriment of citizens.
2. The only way to be granted asylum is if you're already in the US. The only way to enter the US legally is using an intentionally overloaded system that may require you to wait for months only to be denied entry -- which is not exactly an option if you're genuinely in need of asylum.
3. Corporations drive down wages. Corporations are exploiting illegal immigrants. Maybe the problem is your government isn't cracking down on illegal employment enough?
4a. I see you don't agree with the concept of asylum. That's okay, but it still makes you a terrible human being. Just saying.
4b. Show me a study that proves that immigration is a long-term net negative. There are cherry-picked samples showing short-term negatives, yes, but they're intentionally misleading.