Any of the WWII simns are just games, with flight models usually tweaked from some earlier sim. I seriously doubt if an average person with no flight training could get a P-51D off the ground. But EVERYONE can do it in a PC sim. What does that say for accuracy? People with no tailwheel training would also very likely never get one down and stopped without a groundloop but, again, everyone in a PC simulator can do it.
Get a WWII fighter at 250 mph, bank to ... say ...75°, and pull has hard as you can. Think you'll get a turn or a whip-stall / spin after a wind-up? The sims all get a pretty decent turn from that maneuver.
"Any of the WWII sims" is now a little exaggerated. Though what you describe certainly stands true for most "older" sims, if you play, say, DCS-51 you'll certainly find that landing is no longer an easy task, and you will stall and spin as soon as you try to pull the stick with no regard to basic airmanship. Though sims still have innate limits (fied of view and no G-load, for example) the "hardcore" ones have improved a lot in the last years.