Not picking sides, but those are canned lists that have been floating around for a long time. That is not research. Note the bias of the list:

First democrat entry
Richard Gephardt: Air National Guard, 1965-71.

Comparable service from the republican list
George W. Bush: six-year Nat’l Guard commitment (infour).
Issues of desertion and unfitness.

Yeperoo, no bias there. The first one states the facts (fine), the second’s got the slant.

If it were an unbiased list, it would just print the facts and it would be complete.