You can't rehabilitate these people. What you can do is make them feel betrayed so they point in the right direction, then later shame them back into keeping their racist bullshit buried deep down
They're never going to fully accept that ethnic cleansing is wrong, or even that it wouldn't accomplish their goals, but they can be made to understand it's not socially acceptable to share those opinions
And doing that makes them even think about it less. But deep down, people who cheer these camps and ICE raids will always be deeply racist and lacking in compassion. This isn't ignorance, this is naked desire for an enthnostate.
That degree of racism will always be there, and must always be kept under the surface by social pressure