I have no experience with HSFX but the plane structural tolerances were a 4.10 feature from TD and I think HSFX just plugs in on top of those features. So... my assumption for why you notice it more on a Spitfire than on something else is probably because the Spitfire can pull G's very quickly while some other types can't.
There are aircraft that are worse... the Mustang and Tempest have even more effective elevators and are able to pull significant G's very quickly at high speeds. My guess is that they are both more tolerant of G forces as well but it hardly makes a difference as they can overload even quicker from my experience.
On the other end of the spectrum I can hardly ever exceed the G tolerances on a A6M5 Zero as the elevator isn't very effective at high speeds and it's more difficult to pile on the G forces. It's not impossible either I should say.
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