...and don't take this personally--it isn't the first time I've read or heard something like this.
Arguendo, variations in human thinking and behavior are manifest, and influenced by genetic and physiological factors. Whether "we are products of randomness", or truth merely relative does not follow from the above, however--those are the conclusions of other, unsaid arguments, or stem from some worldview. Those two statements may indeed be true, but they're just being asserted without basis here. This seems to be the blind spot for many who otherwise encourage the strict application of empiricism.
Conversely, is it not possible that there may be some absolutes, or some truth or truths out there, for which we humans reach but might not grasp, that nonetheless exists regardless of our acknowledging it?