Gooseneck to 5th wheel adapter

So I hate to bring up an old topic but I'm looking at a used 5th Wheel with a Gooseneck adapter. Actually the GS adapter was my plan regardless due to truck bed use and convenience. Warranty isn't an issue but I don't understand how the gooseneck hitch puts more "stress" on the frame when a 5th wheel hitch puts both the truck and trailer frame under extreme stress when trying to maneuver into or out of on a non level surface like a forest dry camp spot when the gooseneck adapter allows more freedom??? Of course the other issue is damaging the camper or bed rail if it pivots too much.