Let's say the tapes in question are only of dead guys, only concerning dead guys.

Why are these withheld from public consumption?

Meanwhile, every single Nixon tape has been publicly released, as have almost all candidly taped conversations by LBJ, JFK, Eisenhower, and FDR.

If they can release tapes of Presidents - even ones involving hallowed figures and harming their legacies- Nixon talking say about blacks badly with Billy Graham on the line -

Why can't they release wiretaps of Carlo, if there are any, Paul, Sammy the Bull, other guys from other Families?