I have the same car - I have not found a way to turn that off. Generally speaking, in nearly all cars and nearly all stereos, it's impossible to get rid of the message without "hacking" the software.
Basically, the manufacturers are worried that if they let people turn off the message, and then someone wrecks their car while playing with the stereo, they'll get sued. ("I bought the car used, and it never displayed the message because Kia let the previous owner turn it off, and now I have a permanent limp!")
Like most things in life these days, our life is complicated and inconvenienced by people who are lawsuit-happy. A bag of airline peanuts that says "caution, may contain nuts" comes to mind.