By far the most important fact is regarding fresh pond stocking of fingerlings/fries. While I appreciate the opposing fact, but about the only thing that clears up is a narrow ecosystem of pond stocking. A pond in Ohio does not reflect a pond elsewhere. If a lake is such that has abundant shallowness of weed and structure suitable for the Green Sunfish, then yes they will out compete your brood of Bluegill and Baby Bass. If the lake has a deep water ecosystem that supports the movement of Bluegill and Bass into deep water or openwater during the warmer summer months where Green Sunfish don't move into. Then there is a clear separation of foraging. Thus the Green Sunfish cannot compete for that food source, else they being small will become food for the larger predators of the more open water variety. Furthermore the reason why some panfish move out to openwater is to avoid predation by the lake's top predator. Those Green Sunfish are food.
I've heard many people complain about Green Sunfish outcompeteing other species, but those people merely don't know about openwater fishing for panfish out in the middle of the lake, nor are they aware of finding Bass schooling in deep water either structure oriented or roaming the expanse after open water forage species. Even from shorefishing, if I'm catching Green Sunfish in the shallows and want to catch something else, I go straight to the open water and many times I find openwater Bluegills or Pumpkinseeds. Never a Green Sunfish out there. If they're out there, those Bluegills or Pumpkinseeds are getting first dibs, long before I can retrieve my lure close enough to shoreline structures or weeds for any Green Sunfish.