I agree with your analysis regarding the difference between systematic naming systems and merely similar naming. That said, the justification for more clearly separating Pascal's mugging and this other unnamed situation does strike me as a political decision or rationalization. If the real world impact of people's misunderstanding were beneficial for the AI friendly cause, I doubt if anyone here would be making much ado about it. I would be in favor of renaming moissanite to diamand if this would help avert our ongoing malinvestment in clear glittery rocks to the tune of billions of dollars and numerous lives, so political reasons can perhaps be justified in some situations.