If having studied art makes one more of an authority on art...why does one having studied Egyptology make one less an authority of Egypt in so many eyes?
Because one is much more subjective than the other.
There are far fewer facts in the study of art and a much bigger role for subjectivity and personal "taste". (I'm talking about doing practical art rather than a historical course. I did Fine Art which led to becoming a Graphic Artist)
You can attack a work of art because you "don't like it".
You can't do that with facts about Ancient Egypt so people who disagree tend to attack the source. People with alternative opinions like to disparage those who have studied the subject in the hope that will appear to weaken their arguments.
I'm not saying all people who have alternative opinions do that as I actually hate breaking things down to "Orthodoxy" and "Alternative".
There are just ideas and that's what Maat's about. Weighing them up and rejecting the ones that don't hold water.
This is getting way off topic...