ExploderWizard
Hero
Maybe they believe that fantasy vietnam is the best way to learn D&D. Maybe you just have a preference for a style of game and that results in a bias in your assumptions about D&D players in general.
There are lots of possible reasons the game keeps refusing to go your way in the design. They could be wrong in their assessment of the playerbase and newbie needs. They could be spot on and your out of touch.
My personal gut bias is that players are adults and character death is not the end of the world.
From my own experience, character death wasn't a big deal when I was kid either generally. There was resentment if the player thought the DM was trying to hose him on purpose (which happens with kids) or if a character got betrayed and killed by another player's character (which also happens with kids). Overall though, death which happened while normally playing the game was accepted as a consequence of the events of play being a GAME.
Not every loss was a death or TPK but both were quite common. Adventures are dangerous. Grab the dice and roll up a new character or play a henchman/npc until you can do so. The important thing was to keep the PLAYER involved in the game. Characters are imaginary and disposable. People matter.
Yes, I would have personally fudged the damage to leave the PC with 1 hit point.
Or just have all the players play orc PCs. They would all get a save to keep 1 hit point.

Bold added, in favorable conditions the bugbear should be able to outright kill a character, they are the scary sneaky kind of goblins, for a first level party, if he gets the drop on you it's probably gona hurt.
I love monsters like that, they bring the exploration pillar and the combat pillar together like no other.
Warder
Yes indeed. Knowing that something could pop out any minute and kill you instantly was what made the exploration game so tense and exciting. Just walking around and exploring as a 1st level character in B/X you felt like you were in that scene from Big Trouble in Little China when a monster sprang out of a hole in the wall and just ate a member of the expedition in one gulp.
No assumption based on what the rules should or should not do is needed as the Development after Lost Mine of Phanladin's Goblin Ambush (Pg. 7) encounter specifically says:
''In the unlikely event that the goblins defeat the adventurers, they leave them unconscious, loot them and the wagon, and head back to Cragmaw Hideout. The characters can continue on to Phandalin, buy new gear at Barthen's provision, return to the ambush site and find the goblin trail.''
Its a Go Directly to Jail, Do Not Pass GO, Do Not Collect 200$ sorta thing, No death saving throw needed, the scenario propose having the adventurers not die if they took a rough beat, just knocked unconscious so they can continue after....
I read that and giggled. What are the PCs supposed to buy new equipment WITH?

If you are saying "I personally think that not being able to be killed in one blow is what is best for new players" then fine. If you are saying though that other players including new players all agree with you then I take exception. That was my point.
There is no evidence that I've seen that indicates new players have any more issue with dying than old players do. Some don't mind and some do. It could just as easily be presented that a new player might think D&D is too easy or is not suspenseful. People quit D&D after a session or two all the time. I don't think most of them are retainable. I do think roleplaying is not for everyone. Most of the time, I believe those it is good for will stick with it even if their character dies in one blow.
And that is just my opinion.
Anyone approaching the experience as a game which can include both victory and defeat shouldn't have a huge problem with it no matter their age.