Same logic could apply to Enron or Bernie Madoff. Fraud is fraud, even if it's perpetrated against the rich. Besides, many of the biggest investors are actually defined-benefit pension funds for teachers, firefighters, etc.
In general, there's no actual fraud. It is not fraud to have a bad or unworkable idea and raise money on the basis that the idea is good (unless you _know_ that it's bad or unworkable). Now, once you know it's unworkable, then you're getting closer to fraud, and once you incorrectly claim that it _does_ work, then you're in fraudsville.
Theranos is a neat example of this; as far as anyone can see, in the early stages, its generally rather unsophisticated principals and employees geniunely seem to have thought what they were trying to build was viable. If, once this became apparent, they'd given up, then investors would have lost a lot of money but there would have been no fraud. Instead, they faked it. _That_ was fraud.
If there's fraud, then prosecute it legally. But I am in no way obligated to feel any sympathy to investors getting fleeced. It's their responsibility to do their own due diligence, and if they're getting taken in for, I am hard pressed to give a shit.
Sure you’re not obligated, you just have a pretty rubbish worldview. To be fair so does a lot of the world - buyer beware is a defacto standard, doesn’t mean it’s a moral one though.
OP isn't asking you to feel sympathy for anyone, they're suggesting that there's not a lot of integrity in Silicon Valley. That can be true while at the same time the victims of the outright or borderline fraud are also unsympathetic.
Your comments here seem to suggest that you believe it's actually okay to rob from investors. If that's what you're saying, I think you and OP are in alignment with regards to Silicon Valley ethics.