Some academics also believe there's literally no value in the historical data that technical analysts use, but this is a somewhat flawed argument since the same could be said about past business performance. People do tend to repeat behaviors over and over, which is what technical analysis considers. However, it's unlikely for all the elements that create a behavior to be exactly in line again and again.
Another argument against technical analysis is that results may be more of a self-fulfilling prophecy than an actual result of the analysis, since many technical analysts can influence prices up or down based on their behavior. If everyone is making the same calculations based on the same observations, it's easy to accidentally skew the results in the short term.