Immigration in itself is not necessarily a problem.
The US was basically built from migration, and other countries like Australia are thriving with it.
I think the main issues are either illegal immigration, and refugees. Those are very different to normal migration.
I don't think that anyone in this forum do have an issue with legal immigration. The issue is only with the illegal variety. There are a lot of people out there who would claim that the illegals need to be shown humanity and regimes must tolerate them. But is this the right approach? There are hundreds of millions of poor people in the world. Can the US take all of them? I know the situation here in India. Most of the Indian origin illegal immigrants to USA come from two Indian states - Punjab and Gujarat. These people spend up to $30,000 per head to illegally cross the US-Mexico border. In Indian standards, most of these people and not poor. On the other hand they would rank among top 1% by wealth.