<I think the issues like birth control, homosexuality, divorce and remarriage are too important NOT to leave them to the successors of the apostles.>
But the church has moved on. Nobody, or almost nobody, knows or cares what these guys think about human sexuality.  I'm not even arguing that that's a good thing; but it's a true thing.  By failing to attend to the contributions of scholarship, history and experience, the bishops have forfeited their right to be taken seriously on these issues.
The interesting thing is that their teaching on social issues is received more favorably precisely because it is proposed more humbly; nobody threatens someone with eternal damnation for opposing the social teaching of the church -- but masturbation gets you a ticket to hell. Preposterous.  No reasonable person believes that, but the church teaches it.