The X post in question is indeed authentic; the official @KamalaHarris X account originally published it on April 21, 2017, as part of a longer thread on the topic of immigration and citizenship. The full thread is as follows:
An undocumented immigrant is not a criminal.
Give people a path to citizenship. The vast majority of folks we’re talking about are living a lawful life and paying taxes.
It’s ludicrous to say we’re going to deport 12 million people. Now how are you going to do that?
We are not a society that is going to stand for tearing families apart. We are not going to buy into this administration’s fear mongering.
Americans forget they’re an entire nation descended from immigrants and colonists.
They killed a lot of the natives.
Also that they keep changing which immigrant they hate. Used to be Irish/Italians/Chinese now it’s those from countries we destabilized