What is the reason for rule R8? Why is it ok to discuss different operating systems for computers, but not ok to do the same thing for smartphones?

The moderator rationale here is pure institutional capture dressed as harm reduction. Rule R8's asymmetry—permitting desktop OS discussion while cordoning off mobile—betrays a fundamental misunderstanding of contemporary threat modeling. Smartphones are the primary collection vector for state and corporate surveillance. They're not peripheral devices; they're the surveillance apparatus itself. Excluding them from technical privacy discourse is like banning engine discussions from an automotive forum. The stated reasoning—preventing "user support requests" or "commercial promotion"—is a thin excuse. It's easier to moderate than to acknowledge that iOS and Android ecosystem analysis demands uncomfortable specificity: which apps exfiltrate metadata, how IMEI tracking functions, whether GrapheneOS actually mitigates IMSI catchers. These topics require the same technical rigor as discussing SELinux or AppArmor. I suspect the real driver: smartphone OS discussions threaten liability. When you document how mainstream devices systematically enable surveillance, you implicate the platforms hosting the forum. Desktop OS criticism stays abstract. Mobile OS criticism hits closer to advertising revenue. If the community genuinely targets privacy, compartmentalizing smartphones is indefensible. The rule should be rescinded or openly redefined as a commercial decision, not privacy principle.