I have a Panasonic plasma as well, and aliasing is easily evident when it is present. You simply not noticing or minding aliasing in your setup is not the same as people having their TV's calibrated incorrectly.
In fact, a proper calibration would be displaying things as closely/faithfully to the source as possible, meaning if the source has aliasing then you will see aliasing. No amount of calibration will eliminate aliasing without also degrading overall picture quality severely, as the amount of blurring involved in eliminating aliasing via TV settings would be over the top (so much that no TV I am aware of would even be capable of it).
You just don't notice it or don't mind because of a combination of your screen size, seating distance, and personal sensitivity to aliasing.