Centrist/liberal politicians cannot address immigration concerns, because they don't have those concerns, beyond a matter of logistics, and they don't have those concerns because they don't believe in nativism...
Nativism, an
ideology, governmental policy, or political
stance that prioritizes the interests and well-being of native-born or long-established residents of a given country over those of immigrants, typically by advocating or enacting restrictions on
immigration.
And because centrist/liberal politicians don't believe in nativism, fundamentally they don't see immigration as a problem, beyond controlling the flow and resources, housing, skills shortages and whatnot, they see the issue entirely as one of mechanics. That's why the right wing call them globalists, along with all the other right wing stuff, including abandoning the white working class, trashing our history and being generally unpatriotic.