This private board allows contributions by members only. Free speech here has whatever limits the administrator decides to impose. If the administrator decides that racist, sectarian, homophobic, any other kind of bigoted comments bring down the tone of the discussion and so decides to prohibit them, that's his decision. If you disagree, then leave. If you want a board where any kind of dumb, bigoted commentary is allowed, even if only for the purpose of attracting attention, there's no one stopping you starting another one.