π is not "wrong", that doesn't make any sense. However, I agree with the author that expressing things by using π is more complicated and not as elegant as expressing things with τ.
> It should be obvious that π is not “wrong” in the sense of being factually incorrect; the number π is perfectly well-defined, and it has all the properties normally ascribed to it by mathematicians. When we say that “π is wrong”, we mean that π is a confusing and unnatural choice for the circle constant.