The baud rate on the serial monitor is at its default rate of 9600. What is a baud rate, anyway? Why is it important?
The baud rate is the data rate in bits per second (baud) for serial communication sent between the Arduino and the serial monitor. The rate set in the sketch with Serial.begin(baud rate) must match the rate set in the lower right hand corner of the serial monitor window. If the rate of the arduino and the rate of the serial monitor don't match, the output shown is not valid.
The sketch was written with Serial.begin(115200). Either set the monitor to that speed, or change the sketch to Serial.begin(9600) if that's what you are going to use in the monitor.
The WP pin is connected to ground. That's correct, isn't it? If it were connected to +5V, write protect would be enabled. I basically followed the 24LC128' data sheet and the Sparkfun website.
You are correct. When tied to ground write operations are enabled.
I was uncertain why the sketch did not work properly for you and was searching for possible explanations.
The baud rate mismatch was the root cause.