It is exhibited primarily by so-called Americans, whom the A in "ASCII" stands for, so they feel obliged. These unsophisticated people believe that 128 symbols is quite enough for any possible communication where humans are involved. Inhabitants of the other parts of the world proved this false long ago*; the most aspiring ones went so far as to invent up to five machine character sets for a single alphabet, all incompatible with each other.
As most of the obscurantist, flat-earth doctrines before it, fASCIIsm is doomed. It's going to succumb to the new world order of Unicode and XML.
At least not later than 1000 BC.