If we have to select a single desk height for static work surfaces, then it should be high enough to fit tall people. If tall people can fit, so will smaller people (although they will have to use things like keyboard trays, footrests, etc. in order to find an effective fit). The 29" height is represented as the height necessary to fit a majority of the USA population, and is based on anthropometry data (body sizes) specific to the USA population. Other countries or regions may differ, because their population anthropometry may differ (e.g., populations in southeast Asian may benefit from a lower height, while northern European populations may benefit from a higher height).

The counter argument that other ergonomists put forth, including me, is that there is "no one size fits all" desk height -- or any other dimension, for that matter. One of the primary principles in ergonomics, in fact, is that "one size never fits all." One size may accommodate all, but it will not fit all. A fixed work surface height is therefore viewed as a compromise that detracts from ergonomics.

As I've written before, asking "what is the standard desk height" is like asking "what is the standard waist size for a pair of pants."

The 29" table height is most often put forth by the traditional furniture industry or facility managers who see a fixed dimension as a practical compromise to adjustable work surfaces.