Identity, politics, and the in-fighting of the left

Then I’m very skeptical that there are any motives other than racism/xenophobia or an ignorance of how immigration and economics work. What other reasons would someone oppose immigration, in the present US?

I’m much less confident in my understanding of this issue, and in any case I wouldn’t attribute one position or the other to racism. In my understanding, tariffs are very dumb policy, but not racist.