>>57859836No, that's an over-interpretation, a theory.
As it stands, Slow Start is easily explained by the fact that the Pokémon spends its time sleeping. It therefore has difficulty waking up and going straight to its full potential.
Varoom, which has access to this ability, has a similar logic, with an engine that takes a long time to start up. So ‘the curse’ is irrelevant, it's never even mentioned. Varoom is not cursed.
In PLA, almost all plate holders have the same type of plate as the one they have. Giving the normal type to Regigigas is just the most logical choice, especially when that the other legendaries do exactly the same thing. Oh, and Regigigas isn't the only one who's aggressive.
Why take patterns common to all, and pretend it's ‘proof’, it's just confirmation bias, not the truth.
Regigigas is comparable to Ho-Oh and Lugia, and the Regi are not really the giants mentioned in the myths.