Note: I will try to provide a more Eastern-European perspective on the matter. It happened that the crisis caught me working on financial service software and I have some first-hand experience on how it worked from "inside"
Because financial institution are much more aware of the risks involved by credits and a regular person expects from them to know what they are doing (e.g. better estimation of the risk).
I know a specific case when the borrower could be blamed (this can be included in "straight up lying to the banks" in the comments): he and his wife took two loans in the same day, knowing that the debt checking system was not working real-time (required 1-2 working days), but these are more of an exception, at least where I live.
I will try to justify why is it so hard to blame the consumer.
1. Know how - most financial institutions have clear flows starting from the first offer and ending with the contract closure that use risk assessment, scoring algorithms and so on. Also, "maker-checker" principle ensures that mistakes for computations are minimal.
2. Lack of know how - this works with first point. The vast majority of consumers simply lacked (and still does) basic financial and juridic knowledge. The lack is so great that they even do not know that ("unconscious incompetence"). No regular school taught about these and there was no official campaigns to raise the knowledge (now, the banks and some organizations have such campaigns).
While many people know to go to a service to have a second-hand car checked before buying it, almost nobody thinks about going to a financial consultant and/or lawyer to ask for assistance when taking a 30-year loan.
3. Aggressive sales - all financial institutions were very sales-oriented disregarding any common-sense rules such as "try to take a loan in the currency you have the income in" or "what happens if the variable interest goes to the maximum historical value - can you still pay the installment"? I saw scoring algorithms allowing debt ratio up to 100% for private individuals.
3. Complex financial information - back in 2007 a typical repayment plan could have as much as 20 columns (various taxes, insurance some expressed in local currency, others in contract's currency etc.) making it hard to understand even for software developers, not to mention the actual client.
4. Complex juridical information - the contracts included lots and lots of clauses that were very hard to understand. Many of these clauses were declare illegal after the crisis ("abusive clauses").
5. Inflexibility - most of the financial institutions did not allow to have the contract studied before signing it (you could just read it for a few minutes at their office). Don't like a clause? No problem, we have plenty of customers waiting to buy a credit.
6. Cultural bias - the country I live happens to have the highest home ownership rate. So there is a deep culture bias towards "the right to own a house". It is very hard to beat that and one expects the authorities (and banks) to better regulate house credits (as they are currently doing, having learnt the crisis lesson).