Yes and no. They are federated with many communities, but the larger anti-Marxist instances like Lemmy.world are not federated. That's by design, Hexbear wishes to protect their marginalized members such as their trans, queer, gender-nonconforming, and EM/POC communities.
They defederated with .ca and .world because of all the racism, transphobia and general right wing culture in those instances and that's basically all of the parent comments in here
Idk about .ca but .world defederated preemptively from .hexbear because their admins are selfaware wolves who knew hex would point out their rightwigness.