So it is a regional expression... Here in São Paulo gate is portão and door is porta.
Does this mean it is dangerous with wires sticking out and rough parts or does it mean that the gate is not secure in place?
I understand that both are possible but not in the same context.
The first proposed idea could be used when a mother warns her child: "Don't get closer! The gate is not safe".
The other idea may fit when a person is worried about the gate and say: "The gate is not safe; our property is vulnerable".
What would be, "The gate does not secure"? As in does not close or stay closed...