Economics and TA are similar in that people who don't know the discipline dismiss it as not a valid field. We would never do this with physics, chemistry or even social sciences like etymology or history. Jorge is making a common mistake. It's not more complicated or nefarious than that.
I'd rather not lump Economics with TA.
With that said - TA seems to be different than the fields you mentioned. I don't discount the value of TA, but I think it's being highly abused and improperly applied.
Physics/Chemistry have very comprehensive foundations in both theory and practice that while not perfect, allow for consistently accurate and precise predictions to be made by anyone that's "well-versed" in the field - whereas TA can have scores of experts in the field making analyses that are as noisy as the charts being interpreted. Even a subject like quantum physics that's frustratingly nebulous and hard to comprehend has razor sharp theory surrounding the "hows" the game if not perhaps the "whys" - predictable unpredictability.
History and etymology on the other hand don't have that predictive/empirical power - but that's fine, because it hasn't been the intention of these fields to have it. The beauty of fields like these is that they're great at distilling the noise of past events getting it all to coalesce into a big picture that tells us where we are at the moment and how we got here. I think TA is in this camp and the TA dismissals that occur are a result of trying to make it fit in with the other camp.
TA is not the friend that tells you "Bro, if you finish that whole bottle of whiskey tonight, you're going to need to go to the hospital...tonight.".
TA is the friend that's sitting next to you in the hospital the next day telling you "Well, you finished the first half by 10:00 P.M. and by midnight you were wearing your underwear on your head pretending to be Sam Fisher with an empty bottle of Jack. You can't handle your drank."