Which was always pretty stupid. At best it means the Cylons can't hack the whole ship, just whichever part they exploited to gain access remotely in the first place. But really the Cylons would've needed exploits for each individual system anyway, since simply connecting them with wires shouldn't just do that. And unless those other systems are completely air gapped with no wireless or other access, it would be trivial for them to still gain remote access, or have one of their infiltrators provide a local connection of some kind. AFAIR that was never a plot point, which was odd.