This is critical difference. They did not make the same mistake and especially not in the same way. Patrick should have been in a position to much better understand what is happening in his business.
In an ideal world, maybe that should have been the case. But in this world, it simply wasn't.
It makes no sense to say the lenders should have understood Patricks business enough and in same detail avaliable to Patrick to be able to make the judgement.
Perhaps it makes no sense, but it was in fact true. Patrick's business model and methods weren't a secret. They in fact *did* understand Patrick's business model well enough to make the judgment. If you look, you'll find some of Patrick's lenders arguing about this very issue in this very forum.
Patrick on the other hand should have understood these issues and in the case he does not he should not have made claims about them or pay if they are false. It is much more sensible to say that some lenders should be able to take what they are being told at face value and rely on that.
If so, why can't Patrick take what his borrowers told him at face value and rely on that? Patrick made precisely the same mistake those who loaned him money did. You're excusing his lenders but not excusing him.
Each of the lenders have their own set of assumptions. I would not even claim that two different lenders did the very same mistake the very same way.
I'm not sure I know what you mean by "assumptions". But the mistake was fundamental and inherent in the business model and lending environment. The mistake was failing to realize two things:
1) There's no way to enforce these loans in any court of law. That means if people have any reason not to repay, they won't repay. Many people won't sacrifice their real-world lifestyle and bank accounts to repay a bitcoin loan that can't be enforced anyway.
2) Borrowing from Patrick to invest in Pirate just seemed like too good a deal, especially since people knew they could just default on Patrick without consequences. No method would prevent this, short of actually tracking what each person did with the bitcoins, which nobody would agree to.
This is why Patrick's business failed. And there is no argument you can make why Patrick should have known this that doesn't equally apply to those who loaned him money.
(And, again, this doesn't apply to Kraken, which I think was likely an outright scam.)