Immigration only really causes economic issues with bullshit employee specific visas like H1Bs - those visas trap immigrants in powerless positions where they’re unable to advocate for fair compensation and drive down overall wages.

Everything else is fucking bullshit xenophobia.

Infrastructure is a large issue. Border towns can become saturated, which will reduce living conditions, and when immigrants move to larger cities, they can often have trouble finding places to live. A lot of this can be because of a communication barrier. Sometimes that is because there are too few to translate, but there can also be educational issues. As much maligned as the US education system is, it is better than some others, and when your culture eschews school for an early start at earning a paycheck, communication in any language becomes a challenge.

Many issues can be overcome, or at least minimized, by compassionate workers, which many that work with immigrants are, but there isn’t enough funding to get compassionate people where they are most needed. Supporting increased budgets at the border isn’t always about putting guns on the border, it can be about improving the infrastructure that helps get people where they need to be in more efficient ways. I’m starting to ramble, though, and I think I’ve given a partial answer to your question.

If immigration leads to more unemployment, then that is an economic problem, especially in the hypothetical case where the social benefits system is getting more and more strained by an influx of unemployed people. But generally, I think that you can expect that the immigrants will soon find employment. Besides that, there’s the cultural aspect that @[email protected] mentioned. You could also make the point that the country’s infrastructure is more and more stressed as the population grows, but that is fixable and potentially counteracted by the labour potential of the immigrants themselves (i.e., qualified immigrant work forces can make a large-scale infrastructure overhaul possible that will lead to greater national capacities and a net benefit for the entire population).

Aside from these things, I would argue that most of the other reasons boil down to xenophobia or racism.

Historically, US actually was quite welcoming of immigration, including from Mexico. It tends to ebb and flow. I was taught by an economist that typically you open the flood gates when you want the labor, while restricting it when you don’t. To him, labor works just like goods in supply/demand curves. Flooding a market can drive down value of labor, etc., which can be bad for local workers. Obviously it’s a little more complex, but that’s the jist.

The trouble is, with globalization, one must wonder if that S/D curve is still valid. I imagine it is in some sectors, but in others, those jobs have been outsourced. If this is a bigger strain on demand, then it’s better to keep immigration on lock. That would at least help explain why it’s so hostile currently, but I’m just thinking out loud. I don’t necessarily agree with the economist approach.

It depends a bit on how you define immigration. Is what the Spaniards and English did to the Americas immigration or something else?

If the influx of a different culture is so big that it displaces you and your children like it did to the Native Americans, then I understand that you'd want to stop it.

Housing, job availability and potential erasure of culture. I think it depends on what migrants you let in though. Also some groups forming bubbles and refusing to integrate as well.

Personally though, I think kids watching american media on their mum’s ipads is a greater risk to our culture than Mohammed and his family down the street

Also, some immigrants are more racist than white people. Which is sometimes kind of funny. Although my white friend got beat up in Bradford, so sometimes it isn’t.

Regarding potential societal issues:

When multiple cultures mix together, one of two things can happen:

The second usually happens when both cultures place opposite value in something. For example, one culture places a high value on self and the other places a high value on being in a group, this can lead to a divide between cultures. Eventually, the resentment each group has for each other will lead to violence and other sorts of crime. One culture may think “I made the money for myself,” while the other thinks ,“we should all share the money.” If people don’t learn how to get along, you can probably see how that would increase criminal activity. In most cases, it is usually the expectation that the immigrant adapt to the culture of the new place they have moved to, rather than the new place’s home residents being expected to adapt to every immigrants different country cultures.

It also isn’t good when immigrants enter a new country and do not know the laws of the country they have entered. They may commit crimes that could have been legal wherever they came from, but now someone may be a victim to a crime and the immigrant did not know. Now, usually immigrants that legally enter a country do learn about the basic laws of the country and the basic culture, but ones that enter a country illegally may know nothing about the place they are in. They may continue to act the same as they did in their previous home, which may have very different laws, leading to further divide.