The output is not random. It is dependent on a myriad of factors and provided those factors remain constant, the output will remain constant. While you can enumerate the respective factors and determine what the particular output will be given the specific state of those factors, unless you are willing to do this, for the lay observer, the output is inscrutable and best described as "random" in order to prevent having to make a detailed explanation of the relevant factors that is likely will not be understood by the questioner and is also subject to change without warning.