After the staticcall the result is pushed to the stack, but after we use the iszero opcode, it is popped off the stack, and the result from the iszero is pushed onto the stack.
In this case, it's just 0x00 because iszero returned false because staticcall returned true 0x01.
After the staticcall the result is pushed to the stack, but after we use the iszero opcode, it is popped off the stack, and the result from the iszero is pushed onto the stack.
In this case, it's just 0x00 because iszero returned false because staticcall returned true 0x01.