Many MA look down on TKD because of what TKD in general has become offensive to them. NOT ALL TKD schools do this.... However since it's push into the Olympics TKD world wide has become watered down and become a Sport, not a Martial Art. This is offensive to other more traditional artists. Furthermore, because of it's popularity, there are many more Mc Dojo's that push ever futher watered down garbage to the unknowing public that they call TKD. 5 year Black belts, Unskilled upper belts, lack of application. This is something else that Traditonalist find even more offensive. I guess you could say it's not the art that they look down on, it's how it is being market.