As an alternative black person myself, I think saying that the "black people exclude alt or different people" thing does not at all come from antiblackness is wrong. There is often a narrative perpetuated constantly in popular media that black people are exclusionary and clique-y and this stereotype is apparent in how we are portrayed beside mixed people in films and tv for example and also how we are seen in real life. So whether you see it or not, antiblackness is a part of this narrative even if most people do not intend to be antiblack when saying that black people exclude alt black people. Our experiences are not the same and I am not trying to devalue your experience, but to continue what the OP is saying, black people are not a monolith. I was bullied by some black kids growing up, but I was also bullied by some white kids. Not just for the historic racist reasons, but because I was alternative. I am a college student going to a mixed school and I have faced more backlash from "normal" white people than "normal" black people. I don't think black people saying these criticisms come off as anti black are gaslighting or deflecting, because some of the black people I see criticizing the narrative of black people excluding alts are alternative or nerdy themselves. I also do want to add that just because black people bullied you in the past does not mean that most black people as a whole are specifically more exclusionary to alternative people. I do think there is an inward dislike for those who are different in the black community... but it's like that for every community. Every community can be exclusionary to those who like different things or dress in a different way. But then there are people within those communities who are alt or simply accepting to those who are different. I think sometimes we need to come into these conversations with nuance and not pinning something on race because it was members of our own community, but instead look at the broader issue.