And it's not a principled position on open borders nor open migration but instead part of a double standard. These same people probably cheer on the protests in Mexico City against white gringos in Condesa.
That's how I'd summarize the far left position. The far right one is probably that migrants are bad. And I suppose the middle position is that there's a problem when immigration rate outpaces cultural assimilation.
After some quick googling I can't find any groups that support that.
I did find a poll that shows 64% of Americans support creating some path for undocumented immigrants to get legal status. I'm not sure you could call 64% a far left position though.
That this is being memory-holed, much like the ill-conceived bilingual education initiatives of the 90s, is actually a good sign, as it's proof that we're winning.