If I understand correctly, their posts and comments to communities on other instances will still remain visible to you until your instance specifically blocks them. Hexbear won’t talk directly talk to kbin, but will talk to lemm.ee, and lemm.ee will tell kbin about posts and comments that hexbear users have made on lemm.ee’s communities.
Wait, if they’re not federated, then their comments are still visible?
If I understand correctly, their posts and comments to communities on other instances will still remain visible to you until your instance specifically blocks them. Hexbear won’t talk directly talk to kbin, but will talk to lemm.ee, and lemm.ee will tell kbin about posts and comments that hexbear users have made on lemm.ee’s communities.