Point a) is actually heavily contended. Fraud is not estimated by any credible economist to have had a major (>5%) impact on the financial crisis. In a market situation there is always a disagreement about whether or not a security is worth what it is worth, hence the sale taking place (both sides think they are getting a good deal). There was disagreement about AAA securities of course, but it's very unclear if that is due to market valuing stuff differently or outright fraud. The contents of the loans were not lied about, whether or not they were AAA was not lied about, whether or not they should've been AAA is up for contention.
I don't see your point with b) at all.
If you're a bank it's not like there are a ton of avenues for you to invest your money, and outside of mortgages there aren't a lot of ways to pass the money onto consumers. So if what you want is the bank to pass its new found money onto consumers that's the avenue you want. Unfortunately the last time we did that a lot of unqualified people got loans. So my point is it's tricky.
I don't see your point with b) at all.
If you're a bank it's not like there are a ton of avenues for you to invest your money, and outside of mortgages there aren't a lot of ways to pass the money onto consumers. So if what you want is the bank to pass its new found money onto consumers that's the avenue you want. Unfortunately the last time we did that a lot of unqualified people got loans. So my point is it's tricky.