I won't say anything that hasn't already been said, just a little differently.
If you really hammer on a road bike, you will notice that you naturally move forward on the saddle, and have less or none of your weight on your hands. This is because you are essentially putting all of your weight on the pedals. Now if you stop pedaling hard, but keep your butt on the same place on the saddle, some of your weight gets transferred to your hands. You will naturally slide your butt back on the saddle to achieve a more balanced position and to relieve the pressure on your arms and hands.

So bikes made for powerful riding -- road racing, TT, track -- have steeper ST angles, while bikes made for more relaxed riding -- touring, randonneuring, "comfort" -- have slacker ST angles.

Supposedly, Lemond has unusually long femurs, so he designed bikes for himself with relatively slack ST angles (think of the fitting system using a plumb bob hanging off the knee going through the center of the pedal spindle), but theoretically he would still want a steeper angle for time trialing than for touring.

Finally it should be noted that one degree of ST angle equals about one cm of saddle fore-aft adjustment, so most bikes can be made to fit your preference and riding style given the 5-6 cm of saddle adjustment you can achieve with different seat post offsets plus sliding the saddle rails fore and aft.