The consulate officer gave them bad advice. LPR status is NOT to make things easier for those who just want to visit the US and reside elsewhere. Such is an illegal use of that application. Since they lied, they created the subterfuge about what their intent really is, but it appears by their statements and their past behavior that they are highly unlikley to lawfully use further visas issued and hence they are ripe for denial. You can try to get an immigration lawyer to appeal the fact that this time for once in their life they are NOT lying to the immigration authorities, but it's going to be a tough slog.

