You're assuming more stealth than you'd get if the village is aware that they live near giant country or raids are possible. Even without that one of the evolutionary advantages for teenagers going to bed late and adults waking up early is that there is always likely to be someone awake. This has been confirmed
by a study of a tribe of 30 having no time when there wasn't
someone awake.
Who's talking about "self organizing"? The task isn't complex when someone's yelling "There's a giant! Shoot it!" The big problem is
working out what to do. This in this case has a simple problem that doesn't require much self organizing (nothing remotely as complex as a bucket chain) and someone's awake, has worked out what's going on, and should have taken charge.
The thing is shooting something to beat it down is not something that really requires much organisation. It's not remotely forming a bucket chain or fighting in formation. Everyone can pitch in in their own time and at their own pace as long as they have ranged weapons. Even a few goblins would be
much more of a danger in a night attack - they aren't a huge target, they are a lot stealthier, they can cause confusion, and they are hard to focus fire.
From the person who was actually awake yelling "Giant attack! North End! Shoot it!" it's pretty easy. Goblins are a much harder problem to work out. They're small, sneaky, can be in multiple places at once, and you want to organise to fight them or you get shanked from multiple sides almost in silence. Meanwhile even a 10' giant is taller than most village houses and a 16' giant towers over them so can be seen and shot from most places.
Given that there is a significant difference between being 10' tall and being 16' tall then there's a bit of a difference; single story buildings provide significant cover to it. The AC3 of a hill giant in crude hides is not nice for villagers with THAC0 20 - meaning its 55hp go way further than the 105 of the 5e equivalent.
More importantly the skills
of the villagers are different in different editions. In the 5e example with its bounded accuracy I've assumed sling proficiency for my villagers (and it doesn't really matter anyway with the AC of the giant). Slings are a simple weapon - and a weapon both the wizard and the sorcerer are proficient in in 5e. With 5e rules I therefore consider it expected that villagers on the frontier will be. In 3.X and in AD&D weapon proficiencies are much tighter; in 3.5 the experts will be proficient with slings but the commoners almost certainly won't while in AD&D it's far from clear that a sling or bow is in the top two weapons most level 0 villagers should be proficient with; I'd expect the herdsmen to mostly have slings and the huntsmen to mostly have bows. But there are also self defence weapons like staffs or daggers, agricultural implements like scythes, and militia weapons competing for the slots. If our villagers
aren't proficient with ranged weapons then it's a whole different ball game and going to get messy.
If you go in at night as a giant in 5e you've at least a 10% chance of getting killed by a village.