Identity politics is all about assigning stereotypes to people (and restricting them to those stereotypes), mostly based on what they look like, i.e. the idea that because one is white, they are inherently racist, and anyone who is not white cannot possibly be racist against you, all to play into the communist idea of oppressor vs. oppressed. The closest I've come to that is simply to point out that Natives beat white folks to the Americas, and that white folks committed atrocities against Natives. I never blamed any of that on you or anyone here, nor did I claim you were racist because you aren't Native.
Is this an attempt at gaslighting? Dude, one of them and basically just came right out and said it. Others are just heavily leaning into it. You really have no place trying to talk down to someone about supposedly not knowing what something means.
It's not wrong, no matter how much you wish it to be. It was a joke, meant to remind you that at some point, someone further down your family tree was also once an immigrant, and that if you aren't Native, someone is always going to have one-up on you as far as complaining about immigrants. At no time did I advocate for open borders or unrestricted immigration.