Right, but this is just the same idea: rendering the issue entirely as "left-wing" to create a narrative that "the activist left" "bullies" the Democratic Party into adopting "unpopular positions."
First, regarding popularity, the evidence is that public opinion about immigration shifted substantially during the Trump administration, and then again during the Biden administration. Here is, for example, a post by
Gallup on the issue. You can see in their graph that there was an increase of support for the position "immigration should be increased" and a decrease of support for the position "immigration should be decreased", such that by 2020, more people thought it should be increased than decreased. Gallup also shows that, even as recently as 2023, 82% of Democrats and 59% of Independents thought that immigration should be increased (40/26) or kept at present levels (42/33). The numbers drop considerably in 2024.
Here is another example, from
Yougov. They track the question "do immigrants drain national resources?" In 2020, 45.9% of respondents disagreed and only 28% agreed. Then they start converging. "Agree" only goes past "disagree" at the end of 2022, and the gap only becomes substantial in late 2023. And another example, from
Democracy Fund. They show that there are 20 points swings in favor for ideas like "favoring a path to citizenship for undocumented immigrants", "make it easier to immigrate to U.S.", and "undocumented immigrants make a contribution to society" among Democrats, from 2011 to 2024. Similar (but smaller shifts) occur for Independents; some of these reverse course by 2024, some remain on their higher position. The Fund describes the changes in this way:
That was the context that the Biden administration took office in. Democrats as a whole went very "radical" (in a largely false way) because that was the zeitgeist of the Trump years. You had people like
Kirsten Gillibrand saying they were "ashamed and embarrassed" of supporting accelerated deportations and sanctuary cities in 2018. You had amoral careerists like
Sean McElwee pushing "Abolish ICE." Hell, you had
people in ICE saying "Abolish ICE"! You could try to argue that these activist groups were entirely responsible for the shifts in public opinion, but that raises the question of how activists can go from having so much power over public opinion during the Trump administration, to essentially zero in the Biden administration.
Second, "immigration" support, both broad and specific, is not limited to "the left." Things get tricky here because "the left" can mean anything to anyone. But the reality is that many of the center, center-left people of the Democratic party are quite supportive of immigration. Matthew Yglesias describes it as such:
I mention Yglesias not because you agree with him (you've already said you don't), but because he is not on the left. He works for the Niskanen Center, which characterizes itself as moderate. There is a lot more than "abstract" support for immigration among center and center-left types that are not 'activists' (Yglesias is often complaining about these 'activists'!). That is the other part of the context. These people did not go heavily against Joe Biden for his immigration positions, they did not accuse him of moving 'too far left' during his administration.
Compare that to an issue like Israel. 'Activists groups' completely failed at moving Biden and Harris on Israel, because it's a completely different context: there is strong internal opposition for the activists' position.
There are other issues where the argument can be made more effectively but immigration is not one of them. It simply isn't.