Back in the day, PC's would get strongholds and followers when they hit a certain level. Every crap DM (myself included) would think is was a great idea for monsters to sack one while the PC was away. It was never any fun.
When a player puts a little effort work into something, like a castle, house, or cart, don't trash it without their buyin. It's like a thief stealing their items when they were sleeping.
There are better ways to use these new settings in the campaign.
Nah, this isn't comparable to stealing something while the PCs are sleeping or sacking a stronghold offscreen. The OP's example clearly has the player there so they had agency to do something here, but failed to save it. It's never your stronghold until you've successfully defended it.
The example in the op says nothing about whether it was ever possible to diffuse the bombs in the first place, so it's unclear if there is any element of agency at all, let alone how difficult the scenario is to win if that's even feasible.
I freaking love Apocalypse World. It's one of my favorite systems by far. The world has so much potential to be as expansive as you'd like, and can fluidly adjust to the players actions. I've been running a game for a while (which is currently on hiatus because I have a new baby), and it's a blast.
I think there's a misconception, especially among less-experienced DMs, that the only valid interaction a PC can have with elements of their backstory is through conflict and/or resultant trauma, and while it is certainly a tool in the GM's toolbox to create tension and give real stakes to the campaign, it tends to create a world where nothing is worth investing in emotionally, and the character's personality and actions will reflect that. I mean, imagine you have a family or a community, and it gets torched by the fire-breathing dragon on the mountain. That can certainly foment a strong motivation to go slay the dragon, and if they succeed, maybe the character moves on from the loss (or they don't,) but either way the next time the opportunity for comfort and belonging comes up, they'll be more loathe to engage, because it opens up the possibility of getting hurt again. You effectively push the character (and possibly all that player's future characters) one step closer to being an edgelord rogue with no acquaintances who broods in the dark corner of every tavern.
It is perfectly okay for a PC to visit their hometown and spend quality time with their family with no incident whatsoever. You can also make this family a source of information or plot hooks - if they know their adventurer child is on a mission from god, certainly they'd be keeping their ear to the ground for tidbits whenever any adventurous passersby come through to rest, right? Or perhaps the PC left on bad terms, and this is an opportunity to patch the relationship (or summon the conviction to cut ties altogether, in the case of harmful relationships.) Even without loss, or the threat of loss, a PC can be reminded of why they became an adventurer in the first place and get some character development.