No one said anything about making up crimes. The point is to look at a financial crisis or catastrophic market event with the mindset that functional markets where everyone is playing fair do not behave that way, and that, because the situation is abnormal, a crime is likely to have been committed to set it in those circumstances.
Further, because the complexity and opacity of markets and firms makes finding and proving specific securities fraud instances difficult and expensive, makes pinning those instances on the actual decision-makers difficult and expensive, and makes securing consequences that actually stop the fraud functionally or as a deterrent difficult and expensive, it is prudent and pragmatic to identify those decision-makers and to go after them for anything and everything you can find. If you're a high-powered banker and hedge fund manager who uses sophisticated strategies to fleece millions of Americans out of their investments, you shouldn't get off because investigators can't get at the smoking gun documents that you burned or hid from discovery. I want them to ignore the small-fry and go after you with everything they've got.
We did not do this after 2008, which is why we are where we are.
So again, the correct question is not a skeptical, "What crime has been committed?", but a willful," What crimes can we find among the people involved here, whatever they are?". I have no moral qualms or compunction about this, and no one who remembers the ravages of the GFC or the last few years will have an issue, either.