Sigh did you read TFA? It's not "just" a matter of establishing effects - article goes into why it's not that straightforward ... as another commenter said TDCS is like using a sledge-hammer to tune a piano. We know that TDCS does "something" but all the hypotheses are "two tailed" which basically means all you can say is there is an effect - not whether it's a good one or bad one. The pseudoscience is claiming these hypotheses are certain.