Comment by staticassertion

Granted, if humans had utility functions and we could avoid utility monsters (maybe average utilitarianism is enough) and the child in the basement (if we could somehow fairly normalize utility functions across individuals so that it was well-defined to choose the outcome where the minimum of everyone's utility functions is maximized [argmax_s min(U_x(s)) for all people in x over states s]) then I'd be a moral realist.

I think we'll keep having human moral disagreements with formal moral frameworks in several edge cases.

There's also the whole case of anthropics: how much do exact clones and potentially existing people contribute moral weight? I haven't seen a solid solution to those questions under consequentialism yet; we don't have the (meta)philosophy to address them yet; I am 50/50 on whether we'll find a formal solution and that's also required for full moral realism.