This "pretending" is not what is being argued, though. What I saw argued was faith that the data interpreted through senses is reliable.
"Empirical" means somethign capable of being confirmed or denied by the senses. Empirical evidence is gathered through the touch, sight, sound, taste, smell, or equipment to do the job for us, and recorded as data. A physical limitation like blindness requires an individual to take sighted things on faith. Empirical data is not independent of the observer any more than it records itself in notebooks.
Along with that intregral component of observer, it gains a quality of interpretation --is it 3 meters? or is it 3.011 meters? or 2.98 meters? Whatever is satisfactory for the purposes of the experiment is its value. Once an experiment is duplicated a few thousand times to the satisfaction of a few, it is widely accepted by others as something on which to develop their own experiments. They don't repeat the experiment again, but take it on faith. Multiply that by a thousand experimenters and you have a thousand more opportunities for inaccuracies to be duplicated, and for cultural and philosophical bias to predetermine results.
In the end, scientific objectivity boils down to a consensus of opinion; but even so, there is no evidence that is not evident "to us" (subjectively).