Retardation, by definition, is something backward, and RISC-V instruction set is backward, since it is empathically not an improvement over what we already have

Retardation, by definition, is something backward, and RISC-V instruction set is backward, since it is empathically not an improvement over what we already have in OpenSPARC or MC68000 in terms of clean design or intuitiveness. Perhaps you rely on the childish and not the engineering use of retardation, whereby I suspect that it's a cultural thing.