3 bites from a deadly venom and I'm still expecting to die
This is the bit that, if I understand him right, [MENTION=22779]Hussar[/MENTION] is querying (and also [MENTION=27160]Balesir[/MENTION]?).
If I am a high level fighter I can take a "hit" from a fire giant and survive. However, given that even as a high level fighter I remain a mortal hero, a literal hit from a fire giant would kill me. It follows, therefore, that a "hit" from a fire giant isn't in the literal sense a hit - it is a blow that I narrowly dodge, or that send me flying rather than cutting me in two, or something similar (as per Gygax's essays on hit points).
Parallel logic suggests that 3 "hits" from a poisonous snake aren't literally bites that inject venom. Yet, by the rules, each requires me to make a poison save or die.
That is the perceived inconsistency of SoD poison with the broader attack and damage mechanics - SoD poison implies that snakes and spiders pose a type of threat, or attack with a degree of accuracy, that fire giants lack. Which makes little sense within the fiction.
I would add - even if you regard hit points as meat, the oddity remains, because hit points are a type of meat that can survive being peppered by arrows or cut in two by a giant, but that can't survive a bite from a snake or spider. Very fickle meat!