I'm weird in that I always use some grease but I dont feel it's necessary with stock bushings.
Because stock bushings do deteriorate when in contact with oil and fluids, and grease generally has PD's in it, I suppose one could argue that the grease could break down the bushing.
Honestly, I feel that a lot of other stuff will wear the bushing out first so I still use a thin smear of grease on contact areas.