I'm pretty ignorant in this field, and usually I've been a day or so behind the posts (missing the window to press for more information), but I feel like there's definitely some contention there.
Suppose I'm a bank, and I lend you $10 to buy apple tree seedlings. You spend all $10 on seedlings as promised.
The person who sold you the seedlings has $10. You have the seedlings. I have an expectation of getting $10 in the future, presumably from your sales of apples.
Because most people repay their loans, I'm confident I'll get the $10 back, and being a bank, my business is lending money. I might treat the $10 loan as $7 on my balance sheet when I decide how much money is safe to lend out.
Then the price of apples crashes. You come to me and say, 'look, there's no way I'll make $10 selling apples in the time I promised to repay you. Best I can do is deliver you the seedlings or sell them to my neighbor for $3 and give you that'. I grumble a little, but take your deal.
The person you bought the seedlings from still has $10. Your neighbor now has the seedlings and $3 less. I now have 3 real dollars instead of 7 hypothetical dollars. In other words, 4 hypothetical dollars disappeared. When I decide how much to lend out, I'll be basing that on $3 I know I have, instead of the $10 I thought I'd probably get back. I don't lend as much money to aspiring orchardists (orchardeers?), and the price of apples rises.
Edit: This fragility is probably a major factor why some people are so against fractional reserve banking (my counting hypothetical dollars as having value) but without that hack, there's no saying I could have lent you the original $10, so it's a bit of a double-edged sword.
The default is a side effect of that outcome, not its cause.
So sure, the loaned money might still be in the system in some naive sense, but value has been destroyed in the asset price? Suddenly a lot less money buys a lot more asset and that's where we find the deflation.
If I borrow 1M for an asset in good times and can't pay it back, the creditor gets the asset and probably gets a good portion of that 1M back. If that same scenario plays out in bad times and my whole street defaults on the same asset at once, there's a resulting fire sale and far more value is destroyed (including being wiped off neighbouring, non-creditor-owned assets of the same type) than money added by leaving the loan sloshing around somewhere else in the economy.
Suppose I buy a painting. I believe it to be an original Van Gogh so I pay $10 million for it. I then find out it is fake, and worthless. Was $10 million (of money) destroyed? Of course not, I just mis-valued an asset. Suppose it then turns out to be real after all. Owing to the fascinating history of this painting it is now valued at $20 million. Was $10 million of money created (relative to the moment when I originally thought it was a Van Gogh)? No. Was $10 million of wealth created? Yes as the world now has one more thing worth $10 million in it.
Money != wealth, even in the materialist sense where wealth consists purely of goods and services. Money is a metric we use to keep track of wealth, and in general it's considered helpful if that relationship holds, so if we're trying to maintain that relation rigorously the central bank should print another $10 million (or create it by making loans) to reflect our knowledge and appreciation of the Van Gogh - if it doesn't then the existing fixed quantity of money in the system will now be representing a greater quantity of wealth, causing deflation.
As I said in my other post I am not an economist by training. If the economists want to call this thing that got created/destroyed here "money" then I guess I should let them, but I would like to hear a good reason why it makes sense to do so, and I haven't heard one. Absent of a good reason I might as well call it haddock. Or, considering the OP was asking which things that could be explained better, we could acknowledge what any good programmer knows: part of a good explanation is choosing the right names for things.